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Influence of local and landscape environmental factors on alpha and beta diversity of macroinvertebrates in Andean rivers

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Journal of Mountain Science 2023年第9期20卷 2487-2501页

作者： DIAZ-ROJAS Camila A PEDROZA-RAMOS Adriana X barrera-herrera july a ROA-FUENTES Camilo A Ecology Unit in Aquatic Systems Research Group Pedagogical and Technological University of ColombiaUPTCAvenida Central del Norte 39-115TunjaBoyacáColombia

Research on macroinvertebrate community structure in Andean rivers has been oriented towards describing patterns of alpha and gamma diversity by taking into account environmental predictors at local spatial scales(e.g.,micro-and mesohabitats).However,the patterns of beta diversity and the importance of landscape-scale variables have been evaluated to a lesser *** objective of this study was to describe the patterns of alpha and beta diversity of benthic macroinvertebrates in the Andean rivers of the Orinoco basin and their relationship with local and landscape environmental variation.A stratified random sampling of macroinvertebrates was carried out at 40 sites(comprising an altitudinal range of between 500 and 2900 m.a.s.l.),local and landscape variables were *** results showed that the variation of alpha diversity was influenced by local and landscape variables,which are directly and indirectly related to the contribution of sediments,substrate composition and flow velocity,providing a heterogeneity of *** beta diversity was explained by the combined effect of local and landscape *** the beta diversity phenomena,turnover was predominant while nestedness presented a minor contribution and both were explained in greater proportion by local descriptors and some landscape variables,specifically those of a geomorphological *** results concur with the view of an environmental and spatial hierarchy within the river habitat and highlight the influence of multiple scales on macroinvertebrate *** above suggests that both local and landscape scales must necessarily be considered for environmental management and the conservation of Andean lotic ecosystems.

关键词： Andean lotic systems Andean agroecosystems Instream habitat Landcover Turnover Nestedness

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我见过银河，却只爱你这颗星

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2018年

作者： july

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Agglutinin activity in hemolymph of Chinese shrimp and induction effect of Vibrio

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Acta Oceanologica Sinica 1998年第3期17卷 357-361页

作者： Luo Rixiang(Received May 30, 1997 accepted july 20, 1997) Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China

Experiments showed the agglutinin activity in the hemolymph of both spring wild parents and autumncultured individuals of the shrimp Penaeus chinensis Osbeck with the body length of 12 - 16 cm as all 32. Thehemolymph of the above shrimps showed agglutinant reaction to all A-, B- and O-type human erythrocytes, with thereaction titer equal to that of rabbit blood cells. However, the agglutinin activity level was enhanced after being in-duced by Vibro, which was 128 after 24 h of induction and reached the peak value 256 after 48 h of induction, thendecreased gradually.

关键词： Agglutinin activity hemolymph Chinese shrimp induction effect Vibrio

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Stability Test for 2-D Continuous-Discrete Systems

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Journal of Systems Engineering and Electronics 2002年第2期13卷 22-27页

作者： Xiao YangInstitute of Information Science, Northern Jiaotong University, Beijing 100044, P.R. China(Received july 25, 2001) Institute of Information Science Northern Jiaotong University Beijing 100044 P. R. China

Models of 2-D continuous-discree system are introduced, which can be used to describe some complex systems. Different from classical 2-D continuous systems of 2-D discrete systems, the asymptotic stability of the continuous-discrete systems is determined by Hurwitz-Schur stability (hybrid one) of 2-D characteristic polynomials of the systems. An algebraic algorithm with simpler test procedure for Hurwitz-Schur stability test of 2-D polynomials is developed. An example to illustrate the applications of the test approach is provided.

关键词： Asymptotic stability Polynomials Two dimensional

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China's Major Non-ferrous Metals Imports & Exports

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China Nonferrous Metals Monthly 2017年第11期 14-15页

作者： (End of july 2017) General Administration of Customs of the People's Republic of China

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Modelling of the Relaxation Least Squares-Based Neural Networks and Its Application

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Journal of Systems Engineering and Electronics 2002年第2期13卷 16-21页

作者： Lu Kongkuo, Chen Zengqiang & Yuan ZhuzhiDepartment of Automation, Nankai University, Tianjin 300071, P.R.China(Received july 5, 2001) Department of Automation Nankai University Tianjin 300071 P.R. China

A relaxation least squares-based learning algorithm for neual networks is proposed. Not only does it have a fast convergence rate, but it involves less computation quantity. Therefore, it is suitable to deal with the case when a network has a large scale but the number of training data is very limited. It has been used in converting furnace process modelling, and impressive result has been obtained.

关键词： Backpropagation Learning systems Least squares approximations

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DISASTER INFORMATION THROUGHOUT NATION

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Natural Disaster Reduction in China 1996年第3期 97-102页

作者： (UP to july 18)

ＤＩＳＡＳＴＥＲ　ＩＮＦＯＲＭＡＴＩＯＮ　ＴＨＲＯＵＧＨＯＵＴ　ＮＡＴＩＯＮＤＩＳＡＳＴＥＲＩＮＦＯＲＭＡＴＩＯＮＴＨＲＯＵＧＨＯＵＴＮＡＴＩＯＮ￥（ＵＰｔｏＪｕｌｙ１８）Ａｂｓｔｒａｃｔ：Ｄｕｒｉｎｇｔｈｅｆｉｒｓ...

ＤＩＳＡＳＴＥＲ　ＩＮＦＯＲＭＡＴＩＯＮ　ＴＨＲＯＵＧＨＯＵＴ　ＮＡＴＩＯＮＤＩＳＡＳＴＥＲＩＮＦＯＲＭＡＴＩＯＮＴＨＲＯＵＧＨＯＵＴＮＡＴＩＯＮ￥（ＵＰｔｏＪｕｌｙ１８）Ａｂｓｔｒａｃｔ：Ｄｕｒｉｎｇｔｈｅｆｉｒｓｔｈａｌｆｏｆｔｈｉｓｙｅａｒ，ｎ...

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An Adaptive Identification and Control SchemeUsing Radial Basis Function Networks

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Journal of Systems Engineering and Electronics 1999年第1期10卷 54-61页

作者： Chen Zengqiang He Jiangfeng Yuan Zhuzhi (Department of Computer and System Science, Nankai University, Tianjin 300071, P. R. China)(Received july 12, 1998) Department of Computer and System Science Nankai University Tianjin 300071 P. R. China

In this paper, adaptive identification and control of nonlinear dynamical systems are investigated using radial basis function networks (RBF). Firstly, a novel approach to train the RBF is introduced, which employs an adaptive fuzzy generalized learning vector quantization (AFGLVQ) technique and recursive least squares algorithm with variable forgetting factor (VRLS). The AFGLVQ adjusts the centers of the RBF while the VRLS updates the connection weights of the network. The identification algorithm has the properties of rapid convergence and persistent adaptability that make it suitable for real-time control. Secondly, on the basis of the one-step ahead RBF predictor, the control law is optimized iteratively through a numerical stable Davidon's least squares-based (SDLS) minimization approach. Four nonlinear examples are simulated to demonstrate the effectiveness of the identification and control algorithms.

关键词： Neural networks Adaptive control Nonlinear control Radial basis function networks Recursive least squares.

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Theirregularbrokenwaveforcesonverticalwall

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Acta Oceanologica Sinica 1998年第3期17卷 387-398页

作者： Li Yucheng, Liu Dazhong, Qi Guiping ,Su Xiaojun (Received April 21 , 1997, accepted july 2, 1997) Department of Civil Engineering Dalian University of Technology Dalian 116023 China

A method for the calculation of total horizontal wave forces by irregular broken waves on vertical wall is developed, which is based on physical model test. Dimensionless analysis and assessment of real construction. The method for the determination of pressure distribution of horizontal forces on vertical wall as well as uplift forces on the bottom of the wall is also recommended. The results calculated by this method well accord with samples of real construction.

关键词： Irregular waves broken waves wave forces.

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编程之法

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作者： july

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