in the previous studies, the rate of primary infertility was reported differently. it seems the main reasons are related to the different methods of data collection and information analysis. therefore, introducing a precise method to determine the infertile couples and the population exposed to the risk of infertility is an important issue to study primary infertility.the proposed methodology f...

In 1996 Nowak and his colleagues proposed a differential equation virus infection model, which has been widely applied in the study for the dynamics of hepatitis B virus (HBV) infection. Biological dynamics may be described more practically by discrete events rather than continuous ones. Using discrete systems to describe biological dynamics should be reasonable. Based on one revised Nowak et a...

This paper focuses on a fundamental input parameter for most existing mathematical models of pandemic influenza, the ‘basic reproductive number R0,’ defined to be the mean number of new influenza infections created by a newly infected person in a population of all susceptible people. We argue that R0 is limited in policy and scientific value as is any single parameter attempting to characterize...

The impact of an insect-free artificial diet provided at nymphal and/or adult stage upon the developmental rate, life table parameters, and fertility table parameters was examined for Podisus maculiventris (Say). This study showed that when fed an insect-free artificial diet during both the nymphal and adult stage, developmental time was prolonged, preoviposition period was extended, and reprod...

The basic reproductive ratio, R0, is a central quantity in the investigation and management of infectious pathogens. The standard model for describing stochastic epidemics is the continuous time epidemic birth-and-death process. The incidence data used to fit this model tend to be collected in discrete units (days, weeks, etc.), which makes model fitting, and estimation of R0 difficult. Discret...

For populations having dispersal described by fat-tailed kernels (kernels with tails that are not exponentially bounded), asymptotic population spread rates cannot be estimated by traditional models because these models predict continually accelerating (asymptotically infinite) invasion. The impossible predictions come from the fact that the fat-tailed kernels fitted to dispersal data have a qu...

Introductory Population dynamics.................................................................................. 2 Logistic Equation ............................................................................................................ 2 Malthusian parameter ................................................................................................. 3 Carrying capacity................

Insecticide-treated nets (ITNs) are at the forefront of malaria control programs and even though the percentage of households in sub-Saharan Africa that owned nets increased from 3% in 2000 to 53% in 2012, many children continue to die from malaria. The potential impact of ITNs on reducing malaria transmission is limited due to inconsistent or improper use, as well as physical decay in effectiv...

predation rate is basic to any investigation of prey-predator interaction and a major component in the selection of predators for biological control. the predation rate of variegated lady beetle, hippodamia variegata (goze), fed on different densities (20, 40, 60, 80 and 100) of third instar nymphs of cotton aphid, aphis gossypii glover, was studied under laboratory conditions (25 ± 1 °c, 65 ± ...

Bulinus truncatus snail is the intermediate host of Schistosoma haematobium, which causes serious damage to urinary system infected patients. To control it in its rapid interruption and/or elimination disease transmission would be efficient. Copper chlorophyllin (Cu-chl) and magnesium (Mg-chl); two photosensitizers used several biological applications, were bio-assayed against B. snails.  Mg-ch...