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Gianpaolo Scalia-Tomba 《Journal of mathematical biology》1986,23(3):381-392
The asymptotic final size distribution of a multitype Reed-Frost process, a chain-binomial model for the spread of infection in a finite, closed multitype population, is derived in the case of reducible contact pattern between types. The results are obtained using techniques developed for the irreducible case. 相似文献
435.
K. Suneja 《Biometrical journal. Biometrische Zeitschrift》1983,25(4):411-417
This paper deals with two types of simple epidemic models, namely, deterministic and stochastic wherein the latent period is assumed to be positive. In the deterministic epidemic model, the distributions of susceptibles, inactive infectives, active infectives and that of epidemic curve which gives the rate at which new infections take place have been obtained. The expression for the expected time of the entire epidemic has been derived. Also the partial differential equation for the moment generating function of the proportion of susceptibles in the population is established. In the end, we have studied a stochastic approach of the system. 相似文献
436.
A competitive exclusion principle for pathogen virulence 总被引:16,自引:0,他引:16
For a modified Anderson and May model of host parasite dynamics it is shown that infections of different levels of virulence die out asymptotically except those that optimize the basic reproductive rate of the causative parasite. The result holds under the assumption that infection with one strain of parasite precludes additional infections with other strains. Technically, the model includes an environmental carrying capacity for the host. A threshold condition is derived which decides whether or not the parasites persist in the host population.Supported by a Heisenberg scholarship of Deutsche Forschungsgemeinschaft 相似文献
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研究了梨锈病菌(Gymnosporangium haraeanum Syd.)冬孢子角在不同含水量和温度条件下的开裂和繁殖情况,并通过调研及监测手段研究了山西梨产区2019年锈病的发生情况,在此基础上,结合气象因子对梨锈病发生与流行条件进行了探究.结果表明,15~20℃条件下,发育成熟的梨锈病冬孢子角浸水10min可开裂,12h可检测到冬孢子和发育的担孢子;山西省梨产区锈病发生程度从北到南依次加重;4月份降水后平均温度≥15℃的环境条件,是诱发锈病发生的主要因子,为防控的关键点. 相似文献
439.
Two models are studied to describe the spread of foot-and-mouth disease during the 1973 epidemic in Austria. The models are modifications of a three-class-model (due to KERMACK and MC KENDRICK ) taking into account the special character of the disease as well as control methods (stamping-out-method, vaccination programs). 相似文献
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《Cell reports》2020,30(13):4540-4550.e3