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991.
W.D. Reekie 《Research Policy》1973,2(3):246-264
In this paper the patenting activity of the international pharmaceutical industry in London between 1900 and 1966 is analysed. Although patent data as a measure of industrial activity is not without defects it can be used both as an adjunct to and as a surrogate for more conventional yardsticks such as concentration ratios, sales statistics and so on. The results indicate that patenting activity can be used as both an absolute and relative indicator of an industry's pace of technological change. They help pinpoint the international distribution of pharmaceutical research and development. If analysed by product or process they can aid in the understanding of why an industry's competitive behaviour is or is not primarily one of price rivalry. Finally, they illustrate the continuing role of the individual inventor. 相似文献
992.
993.
Yogita S. Raut Uma S. Bhartiya Purushottam Kand Rohini W. Hawaldar Ramesh V. Asopa Lebana J. Joseph MGR Rajan 《Indian journal of clinical biochemistry : IJCB》2016,31(1):99-103
The aim was to study the genotoxic effect of high concentration of thyroxine (T4) in vivo in peripheral blood lymphocytes (PBL) of the patients suffering from thyroid disorders. The effect was compared by performing in vitro experiments with addition of increasing concentration of T4 (0.125–1 µM) in whole blood samples from healthy donors. Cytokinesis-blocked micronuclei (CBMN) assay method was used to assess the DNA damage in the PBL. The study included 104 patients which were grouped as control (n = 49), hyperthyroid (n = 31) and hypothyroid (n = 24). A significant increase in micronuclei (MN) frequency was observed in hyperthyroid patients when compared with the hypothyroid and euthyroid group thereby suggesting increased genotoxicity in hyperthyroidism (p < 0.001). A significant increase in MN frequency was observed at T4 concentration of 0.5 µM and above when compared to lower T4 concentrations (0.125 and 0.25 µM) and basal in in vitro experiments (p = 0.000). The results indicate that the T4 in normal concentration does not exhibit the genotoxic effect, as observed in both the in vivo and in vitro experiments. The toxicity of T4 increases at and above 0.5 μM concentration in vitro. Therefore acute T4 overdose should be handled promptly and effectively so as to avoid the possible genotoxic effect of high concentration of T4 in vivo. 相似文献
994.
The decade of the 1970s heralded a major research effort into mariculture of economically important red and brown seaweeds. Limited and declining natural populations, lack of synthetic substitutes for the phycocolloids, and their upwardly spiralling costs have emphasized the need for more research in this area. Algal mariculture is now technically and scientifically feasible, but the economic realities are still undetermined. This article examines what is known about seaweed mariculture and discusses where future research efforts must go. 相似文献
995.
Technological transitions as evolutionary reconfiguration processes: a multi-level perspective and a case-study 总被引:6,自引:0,他引:6
This paper addresses the question of how technological transitions (TT) come about? Are there particular patterns and mechanisms in transition processes? TT are defined as major, long-term technological changes in the way societal functions are fulfilled. TT do not only involve changes in technology, but also changes in user practices, regulation, industrial networks, infrastructure, and symbolic meaning or culture. This paper practices ‘appreciative theory’ [R.R. Nelson, S.G. Winter, An Evolutionary Theory of Economic Change, Bellknap Press, Cambridge, MA, 1982] and brings together insights from evolutionary economics and technology studies. This results in a multi-level perspective on TT where two views of the evolution are combined: (i) evolution as a process of variation, selection and retention, (ii) evolution as a process of unfolding and reconfiguration. The perspective is empirically illustrated with a qualitative longitudinal case-study, the transition from sailing ships to steamships, 1780–1900. Three particular mechanisms in TT are described: niche-cumulation, technological add-on and hybridisation, riding along with market growth. 相似文献
996.
In this essay, I argue that popular entertainment can be understood in terms of Husserl’s concepts of epochē, reduction and constitution, and, conversely, that epochē, reduction and constitution can be explicated in terms of popular entertainment. To this end I use Husserl’s concepts to explicate and reflect upon the psychological and ethical effects of an exemplary instance of entertainment, the renowned Star Trek episode entitled “The Measure of a Man.” The importance of such an exercise is twofold: (1) to demonstrate, once again, the fecundity of the methodological procedures Husserl bequeathed to us; more than any other philosopher, he tapped into the fundamental manners in which we lose, make and remake the meanings of our lives; and (2) to demonstrate how popular entertainment, similarly, plays a central role in the making and remaking of the meanings of our lives. If my zig-zag procedure between Husserl’s philosophy and popular entertainment is productive and cogent, in addition to elucidating Husserl’s philosophy, it will demonstrate the reality-generating potency and the constitutive power of entertainment in the contemporary world. Entertainment, via ourselves, has become the primary producer of the meanings via which consciousness constitutes the world. 相似文献
997.
Ivan Bradaric Athina P. Petropulu Konstantinos I. Diamantaras 《Journal of The Franklin Institute》2002,339(2):161-187
Higher-order statistics (HOS) are well known for their robustness to additive Gaussian noise and ability to preserve phase. HOS estimates, on the other hand, have been criticized for high complexity and the need for long data in order to maintain small variance. Since rank reduction offers a general principle for reduction of estimator variance and complexity, we consider the problem of designing low-rank estimators for HOS. We propose three methods for choosing the transformation matrix that reduces the mean-square error (MSE) associated with the low-rank HOS estimates. We also demonstrate the advantages of using low-rank third-order moment estimates for blind system estimation. Results indicate that the full rank MSE corresponding to some data length N can be attained by a low-rank estimator corresponding to a length significantly smaller than N. 相似文献
998.
999.
1000.
A performance index consisting of a Chebyshev absolute maximum functional plus terminal and integral cost is applied to the optimal control of dynamical systems. First-order necessary conditions are derived for a large class of systems. Utilizing the necessary conditions, analytic examples are worked in demonstrating many of the properties of this class of systems. 相似文献