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31.
Experiments in which male sea lions (Zalophus californianus) were removed and reintroduced into a social group demonstrate that barking by larger males restricts movement and barking by other smaller males. Barking and aggression were primarily directed toward animals of most nearly equal size. Two 6-year-olds seeking to establish and maintain territorial status used aggressive tactics similar to those observed in breeding males in the field. 相似文献
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Hydrolysis of 2,6-dichlorobenzonitrile in soils 总被引:1,自引:0,他引:1
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The living Laotian rodent Laonastes aenigmamus, first described in early 2005, has been interpreted as the sole member of the new family Laonastidae on the basis of its distinctive morphology and apparent phylogenetic isolation from other living rodents. Here we show that Laonastes is actually a surviving member of the otherwise extinct rodent family Diatomyidae, known from early Oligocene to late Miocene sites in Pakistan, India, Thailand, China, and Japan. Laonastes is a particularly striking example of the "Lazarus effect" in Recent mammals, whereby a taxon that was formerly thought to be extinct is rediscovered in the extant biota, in this case after a temporal gap of roughly 11 million years. 相似文献
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Feline herpesvirus (FHV-1; felid herpesvirus 1 (FeHV-1)) is an alphaherpesvirus of cats closely related to canine herpesvirus-1 and phocine herpesvirus-1. There is only one serotype of the virus and it is relatively homogenous genetically. FeHV-1 is an important cause of acute upper respiratory tract and ocular disease in cats. In addition, its role in more chronic ocular disease and skin lesions is increasingly being recognised. Epidemiologically, FeHV-1 behaves as a typical alphaherpesvirus whereby clinically recovered cats become latently infected carriers which undergo periodic episodes of virus reactivation, particularly after a stress. The primary site of latency is the trigeminal ganglion. Conventional inactivated and modified-live vaccines are available and protect reasonably well against disease but not infection, although viral shedding may be reduced. Genetically engineered vaccines have also been developed, both for FeHV-1 and as vector vaccines for other pathogens, but none is as yet marketed. 相似文献
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Karl A.Dawson 《中国家禽》2001,23(9):32-35
1 简介霉菌毒素是霉菌代谢的次级产物,这种物质很可能在饲料的制造与贮存过程中污染到饲料。目前已知至少有300种以上霉菌代谢产物会使动物及人类中毒,全世界谷物中有25%受到霉菌毒素的污染,而且达到可量测的浓度。在这些毒素中,已知有很多种物质明显影响动物的健康,对动物生产造成重大影响。2 霉菌毒素的产生在自然状态下霉菌毒素的产生是一个全球性问题,但是世界上某些特定地区霉菌毒素产生的情形比其他地区频繁。在较冷或气候较温和的地区,例如加拿大、美国的北部及多数欧洲国家,黄曲霉毒素并不是主要问题,除了进口的饲料原料… 相似文献