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491.
The objective of this study was to demonstrate plantlet formation from cultured mature inflorescences of field-grown orchardgrass (Dactylis glomerata L.) plants. Whole tillers were collected and maintained in the dark at 4°C for either 19 or 25 days before panicle sections were plated on a Linsmaier and Skoog (LS) or Schenk and Hildebrandt (SH) agar medium containing 2,4-D. Generally, better results for both cell proliferation and plantlet formation were obtained with 1) large explants (many florets) on 9.1 μM 2,4-D compared to small explants (few florets) on 1.0 μM 2,4-D, 2) SH rather than LS medium and 3) when tillers were pretreated at 4°C for 25 days rather than 19 days. Chromosome counts of basal leaf cells in 94 regenerated plants showed that no plants possessed the gametic chromosome number of n=14. 相似文献
492.
J D Macgregor J MacDonald E A Ingram M McDonnell B Marshall 《BMJ (Clinical research ed.)》1981,282(6262):434-436
During 1977 and 1978 an unusual epidemic of measles occurred in Shetland, affecting 1032 (5%) of the population. All age groups were represented, and 309 cases occurred in people over 15. Geographical distribution of notified cases ranged from 1% to over one-third of the population aged under 65. All the recognised complications occurred, with a significant excess of respiratory troubles (p less than 0 . 05). Complications were much less common in female patients (p less than 0 . 05). Only about 30% of children under 5 had been vaccinated against the disease, and, based on a sample population, vaccination was found to have had a protective effect of 92%. On cost effectiveness alone, uptake of vaccination by a community as susceptible as that of Shetland should clearly be encouraged and probably given high priority. 相似文献
493.
ABSTRACT This introduction sets out some of the key themes addressed by the papers in the special issue on ‘Confronting the Naturalness of Disaster in the Pacific’. Disasters are now widely understood not as ‘natural’ phenomena but as events or processes that unfold at the intersection between natural or artificial hazards and human populations. We review some of the effects of the naturalisation of disaster before turning to the ways in which Pacific disasters are defined through government, media and public discourses. These discourses feature their own distinctive accounts of possible forms of agency in the context of disaster, and draw on markedly different frames of reference in attributing cause and blame. Similarly, contrasting temporalities and spatialities are invoked in addressing disasters as bounded phenomena. We conclude with reflections on the nature of responses to disaster in the Pacific in the context of increasingly unstable cultural, economic and environmental grounds for action induced by global climate change 相似文献
494.
Enda J. Cummins Shane F. Colgan Patrick M. Grace D. John Fry Kevin P. McDonnell Shane M. Ward 《人类与生态风险评估》2002,8(5):1177-1192
The identification of meat and bone meal (MBM) as a significant factor in the spread of bovine spongiform encephalopathy (BSE) has resulted in the introduction of restrictions on the use and movement of MBM and tallow. This has led to a requirement for alternative uses for these products. This paper reports on a risk assessment performed on the use of tallow as a fuel oil extender in diesel engines. With up to 4000 tonnes of tallow being produced each year in Ireland, combustion with energy recovery represents a viable, cost-efficient utilization route. A stochastic (Latin Hypercube sampling) simulation model was developed to assess the infectiv-ity risk to humans associated with potential airborne exposure to the combustion products when using tallow as a combustion fuel in diesel engines. The model simulates the potential infectivity pathways that tallow follows, including its production from animals with potentially subclinical BSE and processing the tallow with segregation and heat treatments. The model uses probability distributions for the most important input parameters. The assessment takes into account a number of epidemiological parameters that include tissue infectivity, species barrier, disease incidence, and heat inactivation. Two scenarios, reflecting the infectivity risk in different animal tissues defined by the European Commissions Scientific Steering Committee (SSC), were performed. It is seen from the model results that the risk of a human contracting variant Creutzfeldt-Jakob Disease (vCJD) from potential airborne exposure to BSE, resulting from the combustion of tallow, is extremely small even when model uncertainty is taken into account (mean individual risk values ranging from 10-11.43 to 10-7.23 per year/person). The risks are a number of orders of magnitude less than the sporadic annual incidence level of Creutzfeldt-Jakob Disease 9CJD) in Europe (approximately 10-6) 相似文献
495.
P J McDonnell 《The Western journal of medicine》1992,157(4):449-450