We consider a Gause type model of interactions between predator and prey populations. Using the ideas of Cheng and Liou we give a sufficient condition for uniqueness of the limit cycle, which is more general than their condition. That is, we include a kind of weight function in the condition. It was motivated by a result due to Hwang, where the prey isocline plays a role of weight function. Mor...

there are different approaches in philosophical justification of the influences of metaphysical or spiritual causes on the material world. according to the approaches of the the most muslim thinkers, the deposited factors are influencing the on material world, but such influencing is along with the natural and material causes. accordingly, is it possible to propose a methodological materialism ...

The precipitation of asphaltene, one of the components of oil, in reservoirs, transfer lines, and equipment causes many problems. Accordingly, researchers are prompted to determine the factors affecting asphaltene precipitation and methods of avoiding its formation. Predicting precipitation and examining the simultaneous effect of operational variables on asphaltene precipitation are difficult ...

For a family of two-dimensional predator–prey models Gause type, we investigate the simultaneous occurrence center singularity and limit cycle. The is characterized by fact that functional response nonanalytical exhibits group defense. We prove existence uniqueness cycle using new theorem for Liénard systems. gives conditions which surrounds period annulus. results this paper provide mechanism ...

We analyse the behaviour of a multi-sector small open economy with involuntary unemployment due to fair wages. The equilibrium level of employment depends in an intuitively appealing way on the sectoral structure of the economy. It is shown that induced changes in employment are a driving force behind many of the comparative static results. Fair wage variants of the Heckscher-Ohlin and the Rica...