首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
Improved management of diabetic pregnancies at Lautoka Hospital, Fiji, in 1976 resulted in a neonatal survival rate of 100%. Management included attempts to control the maternal blood glucose concentrations with insulin and delaying delivery until there was enough surfactant in the liquor to ensure a viable infant. The techniques are simple to use and require only minimal technological facilities.  相似文献   

7.
8.
9.
10.
11.
12.
13.
14.
Randall, R. M. &; Randall, B. M. 1980. Status and distribution of the Roseate Tern in South Africa. Ostrich 51:14-20.

The Roseate Tern Sterna dougallii population in Algoa Bay is the largest, and now possibly the only breeding population in southern Africa. The two mainland breeding sites at Cape Recife and Kommetjie have been deserted, and in recent years the last remaining breeding site outside Algoa Bay may have been abandoned. Consequently the present estimate of between 70 and 80 breeding pairs in Algoa Bay may represent the entire southern African population. The decline in numbers from hundreds in 1937 is ascribed to human interference. Although the species is rare and endangered in southern Africa, it has a world wide distribution and is in no immediate danger of extinction.  相似文献   

15.
16.
Bird song,ecology and speciation   总被引:11,自引:0,他引:11  
The study of bird song dialects was once considered the most promising approach for investigating the role of behaviour in reproductive divergence and speciation. However, after a series of studies yielding conflicting results, research in the field slowed significantly. Recent findings, on how ecological factors may lead to divergence in both song and morphology, necessitate a re-examination. We focus primarily on species with learned song, examine conflicting results in the literature and propose some potential new directions for future studies. We believe an integrative approach, including an examination of the role of ecology in divergent selection, is essential for gaining insight into the role of song in the evolution of assortative mating. Habitat-dependent selection on both song and fitness-related characteristics can lead to parallel divergence in these traits. Song may, therefore, provide females with acoustic cues to find males that are most fit for a particular habitat. In analysing the role of song learning in reproductive divergence, we focus on post-dispersal plasticity in a conceptual framework. We argue that song learning may initially constrain reproductive divergence, while in the later stages of population divergence it may promote speciation.  相似文献   

17.
18.
19.
《Ibis》1877,19(4):473-474
  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号