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1.
James T. Ziegenfuss Jr. 《Systemic Practice and Action Research》1992,5(5):509-527
This paper discusses the use of the Kast and Rosenzweig systems and contingency model for teaching and practice in organizational analysis and planning, management policy, and organizational development. The need for an organizational model for graduate students and field-based managers and executives is identified. The model is presented beginning with the Kast and Rosenzweig work, with integration of research by Daft, Schein, Trist, Deal and Kennedy, Ackoff, Delbecq, and Mintzberg. The teaching and practice uses of the model in four areas are presented, including organizational analysis and planning, management policy making, and organizational development. In each area case examples of the use of the model in teaching and practice are presented. Needs for future research and implications for the use of the model are discussed. 相似文献
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Chromosomal effects of adeno-associated virus vector integration. 总被引:17,自引:0,他引:17
Adeno-associated virus (AAV) vectors are currently being used in several clinical gene-therapy trials (see the NIH OBA Human Gene Transfer Clinical Trials Database); however, little is known about the chromosomal effects of vector integration. Here we report that integrated vector proviruses are associated with chromosomal deletions and other rearrangements and are frequently located on chromosome 19 (although not at the wildtype AAV integration site). 相似文献
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James W. McAllister 《Studies in history and philosophy of science》2005,36(2):403-410
This discussion note responds to objections by Twardy, Gardner, and Dowe to my earlier claim that empirical data sets are algorithmically incompressible. Twardy, Gardner, and Dowe hold that many empirical data sets are compressible by Minimum Message Length technique and offer this as evidence that these data sets are algorithmically compressible. I reply that the compression achieved by Minimum Message Length technique is different from algorithmic compression. I conclude that Twardy, Gardner, and Dowe fail to establish that empirical data sets are algorithmically compressible. 相似文献
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Submarine hot springs and the origin of life 总被引:2,自引:0,他引:2
The discovery of hydrothermal vents at oceanic ridge crests and the appreciation of their importance in the element balance of the oceans is one of the main recent advances in marine geochemistry. It is likely that vents were present in the oceans of the primitive Earth because the process of hydrothermal circulation probably began early in the Earth's history. Here we examine the popular hypothesis that life arose in these vents. This proposal, however, is based on a number of misunderstandings concerning the organic chemistry involved. An example is the suggestion that organic compounds were destroyed on the surface of the early Earth by the impact of asteroids and comets, but at the same time assuming that organic syntheses can occur in hydrothermal vents. The high temperatures in the vents would not allow synthesis of organic compounds, but would decompose them, unless the exposure time at vent temperatures was short. Even if the essential organic molecules were available in the hot hydrothermal waters, the subsequent steps of polymerization and the conversion of these polymers into the first organisms would not occur as the vent waters were quenched to the colder temperatures of the primitive oceans. 相似文献
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S. S. Tobe R. P. Ruegg B. A. Stay F. C. Baker C. A. Miller D. A. Schooley 《Cellular and molecular life sciences : CMLS》1985,41(8):1028-1034
Summary Titres of juvenile hormone (JH) have been determined in both hemolymph and whole body extracts of femaleDiploptera punctata during the first gonotrophic cycle using a method employing gas chromatography/mass spectrometry for qualitative and quantitative analysis. JH III is the sole JH found in both adult and last instarD. punctata. Maximum values of 1500 ng/ml (6M) were observed at the middle of the gonotrophic cycle, when basal oocyte growth rate was greatest. Changes in rates of JH release in vitro by corpora allata paralleled closely the changes in JH titre, suggesting that biosynthesis is a major regulator of titre. JH levels per animal were calculated from observed JH titres, and at certain time points in the gonotrophic cycle JH levels obtained from analysis of whole bodies were significantly greater than those predicted from hemolymph titres. These results suggest the existence of a nonhemolymph JH pool inD. punctata. Decay in JH titre after allatectomy of 5 day females has also been studied. Following a rapid initial decline, the rate of decay slowed appreciably 4 h post-operation. Thus, use of a first-order rate constant to estimate half-life of JH significantly underestimated the longevity of the hormone. The apparent persistence of JH following allatectomy may be due to the existence of a nonhemolymph JH pool. 相似文献