漓江大型底栖无脊椎动物及其与水环境的关系

为研究漓江上游水库为下游河道枯季航运补水所造成的水生态影响,对漓江大型底栖无脊椎动物空间分布特性与相应的水环境因子进行调查,并采用Shannon-Wiener指数、Simpson指数、均匀度、丰富度指数分析物种多样性。结果表明:纹石蚕、黑龙江短沟蜷为上、中游优势种;纹石蚕、黑龙江短沟蜷、河蚬为下游优势种;纹石蚕、黑龙江短沟蜷为整个漓江水系的优势种。Shannon-Wiener指数、Simpson指数、均匀度、大型底栖无脊椎动物的平均密度和平均动物量均呈现出下游大于中游、中游大于上游的趋势;而物种丰富度指数呈现出下游小于中游、中游小于上游的趋势。大型底栖无脊椎动物和环境因子的典范对应分析表明:温度、电导率、盐度、浊度、水深、总磷、化学需氧量为影响大型底栖无脊椎动物群落结构和分布的主要环境因子。     

三峡库区消落带植被生态学特征分析

 以重庆忠县石宝寨三峡库区消落带为典型案例区,探讨了库区消落带生物多样性指数沿坡面的梯级分布格局,并通过典范对应分析探讨消落带植被生态学特征与环境要素的关联,界定三峡大坝低水位阶段影响消落带植被生态学特征与恢复能力的关键环境因子。相关研究结果表明：库区消落带植被的生物多样性指数随坡面高程变化呈现一定的空间异质性;消落带植被的分布与土壤物性、河边距以及海拔等环境要素具有一定的关联。     

Ahp Cyclodepsipeptides: The Impact of the Ahp Residue on the “Canonical Inhibition” of S1 Serine Proteases

S1 serine proteases are by far the largest and most diverse family of proteases encoded in the human genome. Although recent decades have seen an enormous increase in our knowledge, the biological functions of most of these proteases remain to be elucidated. Chemical inhibitors have proven to be versatile tools for studying the functions of proteases, but this approach is hampered by the limited availability of inhibitor scaffold structures with the potential to allow rapid discovery of selective, noncovalent small‐molecule protease inhibitors. The natural product class of Ahp cyclodepsipeptides is an unusual class of small‐molecule canonical inhibitors; the incorporation of protease cleavage sequences into their molecular scaffolds enables the design of specific small‐molecule inhibitors that simultaneously target the S and S′ subsites of the protease through noncovalent mechanisms. Their synthesis is tedious, however, so in this study we have investigated the relevance of the Ahp moiety for achieving potent inhibition. We found that although the Ahp residue plays an important role in inhibition potency, appropriate replacement with β‐hydroxy amino acids results in structurally less complex derivatives that inhibit serine proteases in the low micromolar range.     

考虑运行水平与稳定性的网络动态评价方法

由于网络评价过程中需要考虑动态性和稳定性等因素,提出一种考虑运行水平与稳定性的网络动态综合评价方法.利用“三次综合”的思想,分别突出评价指标重要性、统计时刻重要性和网络稳定重要性.提出一种基于极小范数的时间度确定方法来集结不同时刻的评价值,提出基于最小差异度的稳定度作用模型,确定网络稳定性对最终评价结果的影响.实例分析表明,所提方法能够在评价结果中有效地体现评价过程的动态性和网络性能指标的稳定性,使得评价过程更加全面,评价结果更加准确.     

A Histogram Matching Approach for assessment of flow regime alteration: application to environmental flow optimization

In this paper we present a Histogram Matching Approach (HMA) for assessment of the flow regime alteration. The HMA uses the degree of histogram dissimilarity as a metric for impact assessment, which is based on the quadratic‐form distance between the frequency vectors of the pre‐ and post‐impact histograms weighted by a specified similarity matrix. The HMA is coupled with an aggregated multiobjective optimization genetic algorithm and applied to a case study on the Kaoping diversion weir (Taiwan) for determining the optimal environmental flow scheme that balances the ecosystem and human needs objectives. Two key issues are addressed in this study. First, we compare the performances of the HMA and existing Range of Variability Approach (RVA). Second, we employ three types of similarity function to investigate their effect on the outcomes of the HMA. The results reveal that the HMA consistently outperforms the RVA in preserving the natural flow variability regardless of what type of similarity function is used. No single type of similarity function can be found that would simultaneously best preserve the natural patterns of 32 Indicators of Hydrologic Alteration (IHA). For the situations where the water‐supply reliability is of critical concern, the pulse similarity is recommended because it would assure the smallest water‐supply deficit. If, however, minor degradation in the water‐supply reliability may be overlooked, the linear similarity is suggested because it would generally result in the post‐impact flows that most satisfactorily resemble to the natural flow regime. Copyright © 2008 John Wiley & Sons, Ltd.     

IDENTIFYING MULTIVARIATE TIME SERIES MODELS

Abstract. This paper is concerned with how canonical variate analysis can be used to identify the structure of a linear multivariate time series model. The procedure used is based on that of Akaike and Cooper and Wood. A correction and a refinement are made, however. The correction is on the testing statistic and the refinement on the allowed order ( p, q ). Appropriate asymptotic distributions for testing zero canonical correlations are also given.     

非线性左、右逆系统的规范形设计

此文对非线性最小阶左逆和最小阶右逆系统给出一种设计方法,其特点是仅用线性程序 (实数矩阵演算)和求反函数的程序即可获得由规范形描写的最小阶左、右逆系统的方程,从而 使设计过程中由非线性带来的复杂性降到了最低限度.     

Assessing dissimilarity relations under missing data conditions: Evidence from computer simulations.

The extensive research examining relations between group member dissimilarity and outcome measures has yielded inconsistent results. In the present research, the authors used computer simulations to examine the impact that a methodological feature of such research, participant nonresponse, can have on dissimilarity-outcome relations. Results suggest that using only survey responders to calculate dissimilarity typically results in underestimation of true dissimilarity effects and that these effects can occur even when response rates are high. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positive and negative opinion modeling: The influence of another's similarity and dissimilarity.

Modeling research that has focused on the effects of observing similar others appears to have underestimated the influence of observing dissimilar others. Two experiments demonstrated that observing a model express liking for a piece of music induced more favorable opinions of the music (positive modeling) when the model was similar to the participant observer in relevant opinions, and more negative opinions (negative modeling) when the model was dissimilar to the participant in relevant opinions. Of note, this pattern was more pronounced when participants also believed their general backgrounds were dissimilar rather than similar to that of the model. Underlying social comparison processes and the mediational role of participants' liking of the model are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The importance of a common in-group identity in ethnically diverse groups.

The purpose of this study was to examine the effects of a common in-group identity in attenuating the negative effects of ethnic dissimilarity. Specifically, it was hypothesized that a common in-group identity would moderate the relationship between ethnic dissimilarity and satisfaction with coworkers. Data were gathered from 87 persons working in groups. Moderated regression analysis provided support for the hypothesis, in that when a common in-group identity was not present, demographic dissimilarity was related to less satisfaction, but when a common in-group identity was present, there was a positive relationship between ethnic dissimilarity and coworker satisfaction. Further, for ethnically dissimilar persons, coworker satisfaction was higher when a common in-group identity was present than when it was not. Results are discussed in relation to the study's contribution to social psychology and diversity management literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)