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91.
E. Cohen 《Cellular and molecular life sciences : CMLS》1985,41(4):470-472
Summary To facilitate massive screening and for structure-activity relationship studies of chitin synthesis inhibitors, methods to obtain the chitin synthetase (CS) containing microsomal fraction from the postmitochondrial supernatant were examined. Compared with fractionation by differential centrifugation, the CaCl2 precipitate yielded the most active CS preparation. Acidification (pH 5.6) and polyethylene glycol 8000 (5%) treatments resulted in relatively low CS activity. Inhibitory effects were detected with polyoxin-D and 1-geranyl-2-methyl benzimidazole, a novel CS inhibitor, but not with benzoylphenyl ureas. 相似文献
92.
Joseph Berkovitz 《Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics》1998,29(4):509-545
In a preceding paper, I studied the significance of Jarrett's and Shimony's analyses of ‘factorisability’ into ‘parameter independence’ and ‘outcome independence’ for clarifying the nature of non-locality in quantum phenomena. I focused on four types of non-locality; superluminal signalling, action-at-a-distance, non-separability and holism. In this paper, I consider a fifth type of non-locality: superluminal causation according to ‘logically weak’ concepts of causation, where causal dependence requires neither action nor signalling. I conclude by considering the compatibility of non-factorisable theories with relativity theory. In this connection, I pay special attention to the difficulties that superluminal causation raises in relativistic spacetime. My main findings in this paper are: first, parameter-dependent and outcome-dependent theories both involve superluminal causal connections between outcomes and between settings and outcomes. Second, while relativistic deterministic parameter-dependent theories seem impossible on pain of causal paradoxes, relativistic indeterministic parameter-dependent theories are not subjected to the same challenge. Third, current relativistic non-factorisable theories seem to have some rather unattractive characteristics. 相似文献
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建立一个有限缓冲区的单服务器模型,证明了在队长有有限二阶矩的条件下,输出过程具强渐近二阶自相似性质与输出过程具强渐近二阶自相似性质等价。 相似文献
95.
Ageing, fitness and neurocognitive function. 总被引:18,自引:0,他引:18
A F Kramer S Hahn N J Cohen M T Banich E McAuley C R Harrison J Chason E Vakil L Bardell R A Boileau A Colcombe 《Nature》1999,400(6743):418-419
96.
R.S.斯特恩 《国外科技新书评介》2006,(12):18-19
高分子概念的形成和高分子科学的出现始于20世纪20年代。当时有些有机化学家开展了缩聚反应及其自由基聚合反应的研究,并通过这些反应相继开发出尼龙(聚酰胺)66、氯丁橡胶、丁苯橡胶和聚甲基丙烯酸甲酯等一大批高分子材料,从而形成了“高分子化学”的研究领域。随着这些合成高分子的出现,解决这些高分子的性能和表征:以及了解其结构对性能的影响等问题也随之变得很必要了。因此从20世纪40年代至50年代,一批化学家、物理学家投入这方面的研究,渐渐形成了“高分子物理”这门新兴的学科。 相似文献
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An erosion of the power of people and their communities to control any more than a fragment of their future continues. Educational and governmental policy decisions are, for the most part, mandated from above and/or outside the community. This paper introduces a model which reflects Freire's humanizing pedagogy. This method is a vehicle, an avenue of empowerment for people and their communities to control their own destiny and the future of their community. The model is Interactive Management (IM) and its derivative, The CogniScope System. IM is a specialized system of management using collaborative teamwork to define and resolve highly complex issues. The process includes the integration of the diversity of perceptions of the participants with regard to the given ssues, builds consensus and joint ownership of the process and/or product, and creates a collaborative action plan to accomplish the participants' goals. The principal intangible outcome of the process, however, is the reflective participation, which leads to action, and the learning that occurs among the community of stakeholders present. The process of Interactive Management (IM), enhanced through the use of the CogniScope System, is described and examples of its application by First Nation peoples are shared. 相似文献
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