337 research outputs found

    Mechanisms linking plant diversity to large herbivore performance

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    There is established concern that loss of biodiversity will affect ecosystem productivity, nutrient cycling, carbon storage, stability and other properties^1,2^. Interactions between trophic levels are thought to link changes to biodiversity and ecosystem processes^3-6^. However, there is a lack of empirical studies linking plant diversity with altered trophic levels^7,8^, especially for large herbivores, the important but often neglected, controlling trophic level in terrestrial systems. Here we examine responses in performance of the large generalist herbivore to changes in plant diversity, using an indoor cafeteria trial and a field experiment. Our results show that increased plant diversity improves herbivore performance but it is depressed at highest plant diversity levels. We propose the Disturbance Selection Hypothesis for explaining plant diversity effects on primary consumers. Increasing the number of plant species in grassland, increases consumption and enhances nutrient intake (presumably improving animal fitness) by modifying nutrient balance, toxin dilution and taste modulation. High plant diversity simultaneously intensifies animal diet switching frequency, and weakens the herbivore's ability to select food, thereby increasing foraging cost and disturbing the herbivore's selection of forage. Thus, the consequence of plant diversity for large herbivore performance depends on the trade-off between the positive and negative effects. At highest plant diversity the positive effects weaken and negative effects strengthen. We suggest knowledge of the mechanisms is the means for understanding relationships between biodiversity and ecosystem functioning, and the management of large herbivores on rangelands used for conservation and grazing

    Research on the Impact Mechanism of the Ambidextrous Innovation of Public Administrators

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    This study draws on the literature of social cognitive theory to examine the impact of leadership self-efficacy on the ambidextrous innovation of public administrators. Afterwards, this study introduces perspective taking as a moderator and then discusses the different moderating effects of cognitive perspective taking and affective perspective taking. Findings show that leadership self-efficacy has a significant positive effect on ambidextrous innovation; cognitive perspective taking and affective perspective taking play important roles in the relationship between leadership self-efficacy and ambidextrous innovation; the interaction of affective perspective taking and leadership self-efficacy is not conducive to the realization of the ambidextrous innovation of public administrators. This study is a pioneering endeavor in the field of innovation research at the individual level in Chinese public sector, thereby providing important implications for public administrators to stimulate their ambidextrous innovation. Keywords: public administrators, ambidextrous innovation, leadership self-efficacy, cognitive perspective taking, affective perspective takin

    The relative isoperimetric inequality for minimal submanifolds in the Euclidean space

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    In this paper, we mainly consider the relative isoperimetric inequalities for minimal submanifolds in Rn+m\mathbb{R}^{n+m}. We first provide, following Cabr\'e \cite{Cabre2008}, an ABP proof of the relative isoperimetric inequality proved in Choe-Ghomi-Ritor\'e \cite{CGR07}, by generalizing ideas of restricted normal cones given in \cite{CGR06}. Then we prove a relative isoperimetric inequalities for minimal submanifolds in Rn+m\mathbb{R}^{n+m}, which is optimal when the codimension m≤2m\le 2. In other words we obtain a relative version of isoperimetric inequalities for minimal submanifolds proved recently by Brendle \cite{Brendle2019}. When the codimension m≤2m\le 2, our result gives an affirmative answer to an open problem proposed by Choe in \cite{Choe2005}, Open Problem 12.6. As another application we prove an optimal logarithmic Sobolev inequality for free boundary submanifolds in the Euclidean space following a trick of Brendle in \cite{Brendle2019b}.Comment: 18 page

    Research on the Balance Between Commonweal and Commerciality in the Development of Social Enterprises

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    Since social enterprise in our country began to appear and expand on the amount and type of industry, the discussion about its identity orientation, characteristics, operation model and future development emerges constantly and becomes a hot topic in academia. But in the emphasis on social enterprise as a kind of commonweal and commercial organization form, whether and how to balance the two sides tend to be ignored. The majority of people insist that social enterprise must exist with the goal of social interests, which makes it's "business" side hard to stand out. In this state of imbalance, the development of social enterprises will face a lot of problems. So obtaining from the related cases, this article aims to explore balance problems between public welfare and commerciality in the process of development of social enterprises in our country at present stage, and proposes corresponding solutions. Keywords:Social enterprise; Commerciality; Commonweal; Amity Baker

    Network Centrality and Public Service Motivation: The Medium of Organizational Commitment

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    Based on social network theory, this paper studies the mechanism of betweenness centrality on public service motivation and how this influence is mediated by organizational commitment. The theory of public service motivation, as a product of the crisis of Western social government, has attracted a lot of academic interest because of its completely different ideas. In the subsequent development, it has become a parallel with Weber's bureaucratic theory, representative bureaucracy, and public choice theory. One of the four theoretical schools that describe bureaucratic behavior. As an emerging topic in the field of public management research, in-depth study of public service motivation not only helps to select a qualified civil service, but also helps to better improve public service motivation in the public sector and accelerate service-oriented government construction pace. Through a questionnaire survey of 206 public sector members, the empirical analysis shows that the higher the betweenness are, the more motivated individuals are. In addition, the organization promises to play an intermediary role between the betweenness centrality and public service motivation. The article's research conclusions, from the point of view of social network theory, enrich the angle and strength of interpretation of public service motivation, and also provide new ideas for the future public sector to further enhance the public service motivation of the organization members. Keywords:public service motivation, betweenness centrality, organizational commitmen

    Multi-stage sizing approach for development of utility-scale BESS considering dynamic growth of distributed photovoltaic connection

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    The battery energy storage system (BESS) is regarded as one of the most promising address operational challenges caused by distributed generations. This paper proposes a novel multi-stage sizing model for utility-scale BESS, to optimize the BESS development strategies for distribution networks with increasing penetration levels and growth patterns of dispersed photovoltaic (PV) panels. Particularly, an integrated model is established in order to accommodate dispersed PVs in short-term operation scale while facilitating appropriate profits in long-term planning scale. Clusterwise reduction is adopted to extract the most representative operating scenarios with PVs and BESS integration, which is able to decrease the computing complexity caused by scenario redundancy. The numerical studies on IEEE 69-bus distribution system verify the feasibility of the proposed multi-stage sizing approach for the utility-scale BESS.</p
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