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51.
Urban Ecosystems - We studied the occurrence of bats in urban parks in the city of Madrid (Spain), and the resulting patterns were compared with bat occurrence in the surrounding region. In this...  相似文献   
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Unions, particularly in Germany, are the subject matter of intense public debates as well as discussions in academic research, which corroborate the former. The last systematically conducted analysis of the status quo in academic research was done in spring 2001. In view of the rather dramatic symptoms of the crisis German unions are facing, it is time to incorporate the latest results of scientific research. This paper addresses this task against the background of a systematic literature review. Three application areas are distilled out of a total of 79 pieces of research that are considered relevant and intensively discussed: (1) the membership in German unions, (2) the unions in the German system of industrial relations and (3) the reformation of the German unions. The detected symptoms of the unions' crisis are impressively documented and explained by the studies. However, shortcomings regarding the respective research questions and the development of recommendations for future courses of action for the unions can also be identified.  相似文献   
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This paper brings together the research on temporary organizational forms. Despite a recent surge in publications on this topic, there have been few attempts to integrate knowledge on what we know of such temporary forms of organization. In order to correct this, an integrative framework is proposed around four central themes: time, team, task and context. Within each of these themes, the paper offers an overview of the literature, the gaps in what we know, and what future directions might be taken by scholars hoping to contribute to this important and rapidly growing field.  相似文献   
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Over the last decade we have witnessed an unprecedented growth in the number of cross-border R&D investments towards large emerging countries such as China and India. However, small middle-income countries have played a marginal role as recipients of R&D-related FDI despite increasing policy efforts. In particular, several Latin American countries have recently launched new policy programs with the aim of attracting this kind of investments, but it remains uncertain whether public incentives can be useful to compensate for other locational disadvantages. The case of Chile provides an interesting empirical setting to explore these issues because during the last decade its government has been actively promoting R&D-related FDI through a new policy mix. This article suggests that for national innovation systems to benefit from the attraction of internationally-mobile R&D it is critical for public policies to ensure that appropriate linkages are established with local actors that hold absorptive capacities. Equally important for a small emerging economy like Chile is to prioritize R&D-related FDI in strategic technology niches where the country can realistically attain critical mass.  相似文献   
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The aim of this paper is to obtain new sharp inequalities for a large family of topological indices, including the second variable Zagreb index \(M_2^{\alpha }\), and to characterize the set of extremal graphs with respect to them. Our main results provide lower bounds on this family of topological indices involving just the minimum and the maximum degree of the graph. These inequalities are new even for the Randi?, the second Zagreb and the modified Zagreb indices.  相似文献   
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A Corporate Culture Pattern to Manage Business Ethics   总被引:2,自引:0,他引:2  
Within the general frame of proposals for an adequate management of business ethics, this paper is based on the vision of corporate culture as a pattern to achieve such purpose. If we consider ethics as a specific value of corporate culture, we may resort to the mechanism of cultural change and implementation in order to manage ethics. Despite the difficulties it entails in terms of time and money investment, this procedure is one of the safest ways to reach ethical values which are known, shared and then practiced by all the members of a corporation, whatever the category. From this central standpoint, and basing ourselves on our own proposal for the management of culture, we shall describe which specific steps must be taken in order to achieve a set of ethical values which are both realistic and furthermore shared by all collaborators of an organization. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
59.
Missing data in clinical trials is a well‐known problem, and the classical statistical methods used can be overly simple. This case study shows how well‐established missing data theory can be applied to efficacy data collected in a long‐term open‐label trial with a discontinuation rate of almost 50%. Satisfaction with treatment in chronically constipated patients was the efficacy measure assessed at baseline and every 3 months postbaseline. The improvement in treatment satisfaction from baseline was originally analyzed with a paired t‐test ignoring missing data and discarding the correlation structure of the longitudinal data. As the original analysis started from missing completely at random assumptions regarding the missing data process, the satisfaction data were re‐examined, and several missing at random (MAR) and missing not at random (MNAR) techniques resulted in adjusted estimate for the improvement in satisfaction over 12 months. Throughout the different sensitivity analyses, the effect sizes remained significant and clinically relevant. Thus, even for an open‐label trial design, sensitivity analysis, with different assumptions for the nature of dropouts (MAR or MNAR) and with different classes of models (selection, pattern‐mixture, or multiple imputation models), has been found useful and provides evidence towards the robustness of the original analyses; additional sensitivity analyses could be undertaken to further qualify robustness. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
60.
In this paper we develop a study on several types of parallel genetic algorithms (PGAs). Our motivation is to bring some uniformity to the proposal, comparison, and knowledge exchange among the traditionally opposite kinds of serial and parallel GAs. We comparatively analyze the properties of steady-state, generational, and cellular genetic algorithms. Afterwards, this study is extended to consider a distributed model consisting in a ring of GA islands. The analyzed features are the time complexity, selection pressure, schema processing rates, efficacy in finding an optimum, efficiency, speedup, and resistance to scalability. Besides that, we briefly discuss how the migration policy affects the search. Also, some of the search properties of cellular GAs are investigated. The selected benchmark is a representative subset of problems containing real world difficulties. We often conclude that parallel GAs are numerically better and faster than equivalent sequential GAs. Our aim is to shed some light on the advantages and drawbacks of various sequential and parallel GAs to help researchers using them in the very diverse application fields of the evolutionary computation.  相似文献   
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