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排序方式: 共有236条查询结果,搜索用时 15 毫秒
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The incidence of tobacco mosaic virus (TMV) Strain 1 in tomato crops of TMV-susceptible cultivars increased from 12% in 1971 to 64% in 1974. This change coincided with the introduction of cross protection to reduce the effects of tomato mosaic. Of the isolates collected from nurseries where the technique was used in 1974, 94% were of Strain 1 compared with 39 % from the other nurseries. No new strains were found and all the isolates were tomato forms of TMV. 相似文献
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Stoats are significant predators of native fauna in New Zealand. They occur in many habitat types and consume a wide range of prey. The diet of stoats in the Tasman River, South Canterbury, was studied by analysis of scats and den contents. Analysis of 206 scats showed that stoats ate mainly lagomorphs, birds and invertebrates. Minor components included mice, lizards, fish and hedgehogs. Stoats ate more birds in spring than in autumn, and female stoats ate more invertebrates than did males. The contents of 219 dens collected in the same area at the same time provided further information. Birds and lagomorphs occurred at high frequency in dens, and other components were minor. Remains in dens were larger than in scats and allowed identification of many more prey items to species level. Den contents revealed a potentially substantial impact of stoats on threatened shorebirds locally; this impact was not detected by analysis of scats. 相似文献
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The global threat of terrorism raises questions about preparedness and risk communication in the context of public health and security. Although experts discriminate between chemical, biological, radiological, nuclear, and explosive (CNRNE) terrorist events, little is known about how the Canadian public represents these forms of terrorism. A stratified random sample of 1502 Canadians participated in a telephone survey on CBRNE terrorism. A word association technique was used to assess first words or images that came to mind while thinking about different types of terrorist scenarios. Content analysis of this data revealed a number of potential uncertainties and misconceptions regarding different types of terrorism scenarios. Despite most frequently providing agents in response questions surrounding chemical or biological terrorism, respondents frequently confounded agents of biological and chemical nature. Similarly, different aspects of nuclear events were not consistently distinguished. Most notably, however, a sizable proportion of respondents had difficulty providing word associations to the different types of terrorist events or only provided vague responses that closely mirrored the scenario in question. Finally, images regarding the potential impacts of scenarios were infrequent. Implications for risk communication and preparedness are discussed; in particular, the need to provide the public with more detailed information regarding the nature of different forms of CBRNE terrorism and how to best prepare for a potential event. 相似文献
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Joel G Ray Loralie J Langman Marian J Vermeulen Jovan Evrovski Erik L Yeo David EC Cole 《Trials》2001,2(3):141-9