Evaluating the probability of silent circulation of polio in small populations using the silent circulation statistic

As polio-endemic countries move towards elimination,infrequent first infections and incomplete surveillance make it difficult to determine when the virus has been eliminated from the population.Eichner and Dietz[American Journal of Epidemiology,143,8(1996)]proposed a model to estimate the probability of silent polio circulation depending upon when the last paralytic case was detected.Using the same kind of stochastic model they did,we additionally model waning polio immunity in the context of isolated,small,and unvaccinated populations.We compare using the Eichner and Dietz assumption of an initial case at the start of the simulation to a more accurate determination that observes the first case.The former estimates a higher probability of silent circulation in small populations,but this effect diminishes with increasing model population.We also show that stopping the simulation after a specific time estimates a lower probability of silent circulation than when all replicates are run to extinction,though this has limited impact on small populations.Our extensions to the Eichner and Dietz work improve the basis for decisions concerning the probability of silent circulation.Further model realism will be needed for accurate silent circulation risk assessment.

Analysis on China Cotton Market

China is the world＇s largest cotton producer and consumer and its domestic cotton demand and supply have a great influence on the world market. This paper firstly gives a discussion on Chinese cotton market, especially from a viewpoint of history to study domestic market price fluctuation. The cotton market history from E R. China＇s setting up to present has been divided into four stages and characterized as different agricultural policies applications and economic periodicities. Concluding from the history, artificial influences may be the most important reason of market inequilibrium, up to now, market and artificial interruption, are also the key problem. Then it takes domestic cotton demand as a study object, trying to find what will be a statistic significant cotton demand in national level and it＇s underneath demand frame. Through a seres of analysis on the demand frame, problems have been clearly displayed, an open microeconomic circulation supports our study and six variables had been described by statistics. Therefore, we can analyze the cases of real cotton demand that includes supply and demand reactions in China with experience and estimations. Otherwise, international cotton market is greatly interacted with Chinese domestic market more and more today. Some necessary analysis, such as international cotton supply and demand, Chinese cotton stock policy and world price long run tendency, are very important factors for Chinese cotton development. Those may concern Chinese access to WTO, cotton trade quota and tariff, welfare comparison, etc., all have been discussed in the paper.

Detailed parametric design methodology for hydrodynamics of liquid-solid circulating fluidized bed using design of experiments

A design-of-experiments methodology is used to develop a statistical model for the prediction of the hydrodynamics of a liquid–solid circulating fluidized bed. To illustrate the multilevel factorial design approach, a step by step methodology is taken to study the effects of the interactions among the independent factors considered on the performance variables. A multilevel full factorial design with three levels of the two factors and five levels of the third factor has been studied. Various statistical models such as the linear, two-factor interaction, quadratic, and cubic models are tested. The model has been developed to predict responses, viz., average solids holdup and solids circulation rate. The validity of the developed regression model is verified using the analysis of variance. Furthermore, the model developed was compared with an experimental dataset to assess its adequacy and reliability. This detailed statistical design methodology for non-linear systems considered here provides a very important tool for design and optimization in a cost-effective approach