A SIR epidemic model with delay, saturated contact rate and vertical transmission is considered. The basic reproduction number 0 R is calculated. It is shown that this number characterizes the disease transmission dynamics: if 0 1 R , there only exists the disease-free equilibrium which is globally asymptotically stable; if 0 1 R , there is a unique endemic equilibrium and the disease persists,...

A stochastic model for the evolution of a growing population is proposed, in order to explain empirical power-law distributions in the frequency of family names as a function of the family size. Preliminary results show that the predicted exponents are in good agreement with real data. The evolution of family-name distributions is discussed in the frame of vertical transmission of cultural feat...

aids is a prevalent disease of our century. fortunately its limited ways of transmission has caused it to be able to be controlled by adopting preventive methods. transmission of hiv is therefore considered as a crime. the point is here:  may the widespread transmission of aids be regarded as an instance of moharaba (insurgency)? the appearance of evidences does not confirm this view, as most j...

In this paper, we formulated a dynamical model of COVID-19 to describe the transmission dynamics of the disease. The well possedness of the formulated model equations was proved. Both local and global stability of the disease free equilibrium and endemic equilibrium point of the model equation was established using basic reproduction number. The results show that, if the basic reproduction numb...

Zika virus is an Arbovirus identified first time in 1947 in Uganda. Zika epidemic is a threat far greater than the Ebola outbreak. The World Health Organization has urged Asian countries to be vigilant about the risk of spreading Zika virus and preventive measures to control it. In Iran, 64 species of mosquitoes from Culicidea family have been reported three of which belong to the Aedes genus, ...