摘要：
Historically, Australia has been important in the study of, and the development of hypotheses aimed at understanding, the evolution of viviparity in amniote vertebrates. Part of the importance of Australia in the field results from a rich fauna of skinks, including one of the broadest ranges of diversity of placental structures within one geographic region. During the last decade, we have focussed our studies on one lineage, the Eugongylus group of skinks of the subfamily Lygosominae because it contains oviparous species and some that exhibit complex placentae. Our specific objective has been to attempt to understand the fundamental steps required when viviparity, and ultimately complex placentae, evolve from oviparous ancestors. We have taken a three-prong approach: (1) detailed study of the morphology and ontogeny of the placentae of key species at the light microscope level; (2) study of changes in the uterus associated with pregnancy, or the plasma membrane transformation; and (3) measures of the net exchange of nutrients across the placenta or eggshell of key species. In turn, we have found that: (1) details of the morphology and ontogeny of placentae are more complex that originally envisaged, and that the early conclusions about a sequence in the evolution of complex placentae was naive; (2) a plasma membrane transformation occurs in viviparous, but not oviparous lizards, and thus may be a fundamental feature of the evolution of viviparity in amniotes; and (3) species with more complex chorioallantoic placentae tend to transport more nutrients across the placenta during pregnancy than those with simpler chorioallantoic placentae but, because the correlation is not tight. the importance of the omphaloplacenta in transporting nutrients may have been overlooked. Also, the composition of yolk of highly matrotrophic species is broadly similar, but not identical, to the yolk of oviparous species. Some of the interpretation of our data within the context of our specific objective is not yet possible, pending the publication of a robust phylogeny of Eugongylus group skinks. Once such a phylogeny is available, we are in a position to propose specific hypotheses about the evolution of viviparity that can be tested using another linea-e of amniotes, possibly Mabuya group skinks. (C) 2002 Elsevier Science Inc. All rights reserved.
摘要：
Automation and intelligent function in performance testing of optical instrument are the key problems in modern detection technology. In this paper a testing system based on the detection in laboratory is proposed and has successfully realized the detection of multi-optical axes" parallelism. This system is on the base of optics, mechanics and electricity, and combines the modern computer technology to gather and process the data obtained in the experiment, finally high-precision quantified results can be gotten, so these results can provide reliable data for the alignment of optical axes. The paper introduces the whole testing system"s design options, system composition, operational principle and software design in detail, and it"s technical difficulties and emphases are also analyzed and discussed.
摘要：
A subsection modeling and dynamic switching method is developed. First, the system is studied and the mathematical models for every time-period are set up. Then, the simulation models for every time-period are established. Finally, a m-function is designed which makes the simulation models for every time-period be linked and the system states be continuous. This method is applied to the simulation modeling of a flying control system, the simulation speed is greatly accelerated.
作者机构：
[向楠; 张六通; 周明勇] Affiliated Hospital of Hubei TCM College,Wuhan 430061;[向楠; 张六通; 周明勇] Zhongshan Medical College,Taiwan
会议名称：
第二次世界中西医结合大会
会议时间：
2002-09
会议地点：
中国北京
摘要：
<正> Objective:To observe the effect of Yiqi Huoxue Huatan treatment(YHH,supplementing Qi,activatingblood circulation and dissolving Phlegm)in protecting vascular endothelium on level of cytological an
