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61.
石贤玮 《四川生殖卫生学院学报》2005,(5):26-30
随着网络信息技术的发展,数字化、网络化信息资源的开发与利用迅速普及,高校图书馆的功能也发生显著的变化:以印刷文献为中心向以数字信息为中心转变;由单一化服务向多样化服务转变;由人工服务向智能化控制转变;由传统的图书存贮、借阅中心将发展成为现代化信息的交流中转站或导航站。本文分析和阐述了网络环境下高校图书馆功能的嬗变特点和规律,提出了具有实践意义的应对策略。 相似文献
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64.
以苏州七子山垃圾填埋场为背景,采用理论分析的方法,探讨山谷型垃圾填埋场合理的渗滤液收集系统的形式和定量计算方法。 相似文献
65.
Neural classifier construction using regularization, pruning and test error estimation 总被引:1,自引:0,他引:1
Mads Hintz-Madsen Lars Kai Hansen Jan Larsen Morten With Pedersen Michael Larsen 《Neural networks》1998,11(9):1659-1670
In this paper we propose a method for construction of feed-forward neural classifiers based on regularization and adaptive architectures. Using a penalized maximum likelihood scheme, we derive a modified form of the entropic error measure and an algebraic estimate of the test error. In conjunction with optimal brain damage pruning, a test error estimate is used to select the network architecture. The scheme is evaluated on four classification problems. 相似文献
66.
Claudine Savy Fatima Moussafi Jacques Durand Jrme Yelnik Axelle Simon Jeanine Nguyen-Legros 《The Journal of comparative neurology》1995,355(3):392-404
The morphology and distribution of dopaminergic interplexiform cells in adult rat and monkey retinas were analyzed to determine any correlation with the function of dopamine in the outer retinal layers. The retinas were processed as whole mounts for tyrosine hydroxylase immunohistochemistry. There was a network formed by the sclerally directed processes of interplexiform cells in the inner nuclear, outer plexiform, and outer nuclear layers running throughout the retina. Their density was higher in the superior retina than in the inferior retina of the rat and was especially high in the superior temporal quadrant. The external network in this quadrant was significantly less dense in the monkey than in the rat, as are the interplexiform cells. The somata of interplexiform and other dopaminergic cells were about the same size in both rats and monkeys. Computer-assisted reconstruction of external arborizations of individual cells showed that external processes lay very close to horizontal and photoreceptor cells and also to blood capillaries. Because they were long, thin, and highly varicose; branched at right angles; and often arose from an axon hillock, the external processes were identified as axons. Therefore, we define the dopaminergic interplexiform cells as multiaxonal neurons, with at least one outwardly directed axon that reaches the outer plexiform layer. The function of the network of external processes from the interplexiform dopaminergic cells is discussed in terms of modulating the release of dopamine to external layers. 相似文献
67.
Global bifurcation structure of chaotic neural networks and its application to traveling salesman problems 总被引:2,自引:0,他引:2
This paper studies global bifurcation structure of the chaotic neural networks applied to solve the traveling salesman problem (TSP). The bifurcation analysis clarifies the dynamical basis of the chaotic neuro-dynamics which itinerates a variety of network states associated with possible solutions of TSP and efficiently ‘searches’ for the optimum or near-optimum solutions. By following the detailed merging process of chaotic attractors via crises, we find that the crisis-induced intermittent switches among the ruins of the previous localized chaotic attractors underly the ‘chaotic search’ for TSP solutions. On the basis of the present study, efficiency of the ‘chaotic search’ to optimization problems is discussed and a guideline is provided for tuning the bifurcation parameter value which gives rise to efficient ‘chaotic search’. 相似文献
68.
Summary The sensitivity of the cochlea is dependent upon maintenance of a delicate homeostatic environment. One mechanism which participates in providing this environment is the autoregulation of cochlear blood flow. This autoregulation is ensured through the interaction of sympathetic, peptidergic and hemodynamic mechanisms. The current study demonstrates an adaptation that also participates in cochlear blood flow autoregulation. Specifically, an anterior inferior cerebellar arterial network is described and the relative contributions of each of its vessels to total cochlear blood flow is measured using laser Doppler flowmetry. The results show that each collateral vessel contributes to the blood supply of the cochlea and that reperfusion is accompanied by hyperemia. These findings suggest an adaptation that provides stable blood flow through redundancy and compensatory potential. Additionally, these observations have implications for experimental models of ischemia. 相似文献
69.
真皮下血管网皮瓣修复感染创面的研究 总被引:2,自引:0,他引:2
目的:探讨真皮下血管网皮瓣的抗菌能力和临床修复感染创面的应用。方法:以家猪为实验动物,在臀部两侧分别形成传统的岛状皮瓣和真皮下血管网岛状皮瓣,用细菌计数、吖啶橙荧光染色测定白细胞吞噬指数和白细胞内杀菌率等方法,进行对比。结果:真皮下血管网岛状皮瓣的抗菌力明显降低。 1989年起临床应用 5例,创面彻底清创后用吻合血管的真皮下血管网游离皮瓣修复,全部成活。结论:该皮瓣抗菌力虽低于传统皮瓣,但仍可用于修复感染创面。 相似文献
70.
Tsutomu Sugimoto Toshiki Takahashi Kiyoshige Inui Takashi Minowa Takao Watanabe Yasuhisa Shimazaki 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2003,51(10):524-527
Ductus arteriosus aneurysm is rare in adults and preoperative diagnosis has not been usually done. We report 2 cases of adult
type ductus arteriosus aneurysm. In both cases, 3D computed tomographic scanning showed a saccular aneurysm originating from
the distal aortic arch toward the left pulmonary artery, which had a notching in the orifice of the aortic side. They were
successfully treated surgically though one was a ruptured aneurysm to the left pulmonary artery. In these cases, 3D-CT scan
was of great value in the preoperative diagnosis of the ductus arteriosus aneurysm. 相似文献