Dynamic models - often deterministic in nature - were used to estimate the basic reproductive number, R0, of the 2014-5 Ebola virus disease (EVD) epidemic outbreak in West Africa. Estimates of R0 were then used to project the likelihood for large outbreak sizes, e.g., exceeding hundreds of thousands of cases. Yet fitting deterministic models can lead to over-confidence in the confidence interva...

The basic reproduction number, denoted by R0, is one of the most important quantities in epidemiological theory ([11], [23]). It is defined as the expected number of new infections generated by an infected individual in an otherwise wholly susceptible population ([2], [12], [23]). Part of the reason why R0 plays such a central role in this body of theory undoubtedly stems from its relatively si...

sugarcane mite, oligonychus sacchari mcgregor, is one of the most important pests of sugarcane plant in khuzestan province, southwest of iran. during a two-year study (2007-2008), the biology of the sugarcane mite, o. sacchari, was investigated on three commercial varieties cp48-103, cp57-614 and cp69-1062 under laboratory conditions (temperature 30±1° c, rh% 60±5 and a photoperiod of 16:8 (l:d...

biological and demographic parameters of the mealybug ladybird, cryptolaemus montrouzieri (mulsant) were evaluated on citrus mealybug, planococcus citri (risso) and obscure mealybug, pseudococcus viburni (signoret) under 24 ± 2 ºc, 80 ± 5% relative humidity and a photoperiod of 16:8 (l: d) h. the mealybugs had a significant effect on developmental time and reproductive and demographic parameter...

In this work we formulate and analyze a mathematical model for the transmission of West Nile Virus (WNV) infection between vector (mosquito) and avian population. We find the Basic Reproductive Number R0 in terms of measurable epidemiological and demographic parameters. R0 is the threshold condition that determines the dynamics of WNV infection: if R0< or =1 the disease fades out, and for R0 >1...

Hyadaphis foeniculi (Passerini) (Hemiptera: Aphididae) is a cosmopolitan species and the main pest of fennel in northeastern Brazil. Understanding the relationship between temperature variations and the population growth rates of H. foeniculi is essential to predict the population dynamics of this aphid in the fennel crop. The aim of this study was to measure the effect of constant temperature ...

Demography is the study of the population consequences of the fates of individuals. Individuals are differentiated on the basis of age or, in general, life cycle stages. The movement of an individual through its life cycle is a random process, and although the eventual destination (death) is certain, the pathways taken to that destination are stochastic and will differ even between identical in...

The entomopathogenic fungus Beauveria bassiana and the predatory mite Neoseiulus barkeri are both potential biocontrol agents for their shared host/prey Frankliniella occidentalis. The combination of the two agents may enhance biological control of F. occidentalis if the fungus does not negatively affect N. barkeri. This study evaluated the indirect effects of B. bassiana strain SZ-26 on N. bar...

The net economic value of reproductive efficiency in dairy cattle was estimated using a stochastic dynamic simulation model. The objective was to compare the economic consequences of reproductive performance scenarios ("average" and "poor") of a cow having a good reproductive performance and to explore which reproductive factors have an important impact on economic efficiency. A "good" reproduc...

Fitness costs associated with resistance to Bacillus thuringiensis (Bt) toxins critically impact the development of resistance in insect populations. In this study, the fitness costs in Trichoplusia ni strains associated with two genetically independent resistance mechanisms to Bt toxins Cry1Ac and Cry2Ab, individually and in combination, on four crop plants (cabbage, cotton, tobacco and tomato...