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121.
122.
Model of the membrane of smooth muscle cells of the guinea-pig taenia coli muscle during transmission from inhibitory and excitatory nerves 总被引:4,自引:0,他引:4
M R Bennett 《Nature》1966,211(5054):1149-1152
123.
Orme CD Davies RG Burgess M Eigenbrod F Pickup N Olson VA Webster AJ Ding TS Rasmussen PC Ridgely RS Stattersfield AJ Bennett PM Blackburn TM Gaston KJ Owens IP 《Nature》2005,436(7053):1016-1019
Biodiversity hotspots have a prominent role in conservation biology, but it remains controversial to what extent different types of hotspot are congruent. Previous studies were unable to provide a general answer because they used a single biodiversity index, were geographically restricted, compared areas of unequal size or did not quantitatively compare hotspot types. Here we use a new global database on the breeding distribution of all known extant bird species to test for congruence across three types of hotspot. We demonstrate that hotspots of species richness, threat and endemism do not show the same geographical distribution. Only 2.5% of hotspot areas are common to all three aspects of diversity, with over 80% of hotspots being idiosyncratic. More generally, there is a surprisingly low overall congruence of biodiversity indices, with any one index explaining less than 24% of variation in the other indices. These results suggest that, even within a single taxonomic class, different mechanisms are responsible for the origin and maintenance of different aspects of diversity. Consequently, the different types of hotspots also vary greatly in their utility as conservation tools. 相似文献
124.
Oxygen consumption by carnivorous reptiles increases enormously after they have eaten a large meal in order to meet metabolic demands, and this places an extra load on the cardiovascular system. Here we show that there is an extraordinarily rapid 40% increase in ventricular muscle mass in Burmese pythons (Python molurus) a mere 48 hours after feeding, which results from increased gene expression of muscle-contractile proteins. As this fully reversible hypertrophy occurs naturally, it could provide a useful model for investigating the mechanisms that lead to cardiac growth in other animals. 相似文献
125.
Common west African HLA antigens are associated with protection from severe malaria 总被引:91,自引:0,他引:91
A V Hill C E Allsopp D Kwiatkowski N M Anstey P Twumasi P A Rowe S Bennett D Brewster A J McMichael B M Greenwood 《Nature》1991,352(6336):595-600
A large case-control study of malaria in West African children shows that a human leucocyte class I antigen (HLA-Bw53) and an HLA class II haplotype (DRB1*1302-DQB1*0501), common in West Africans but rare in other racial groups, are independently associated with protection from severe malaria. In this population they account for as great a reduction in disease incidence as the sickle-cell haemoglobin variant. These data support the hypothesis that the extraordinary polymorphism of major histocompatibility complex genes has evolved primarily through natural selection by infectious pathogens. 相似文献
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127.
Extraction of prostaglandins from human blood 总被引:27,自引:0,他引:27
128.
Detection of H-2 antigens on mouse spermatozoa by the cytotoxicity test 总被引:10,自引:0,他引:10
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