the present article deals with the inter specific competition and intra-specific competition among predator populations of a prey-dependent three component food chain model consisting of two competitive predator sharing one prey species as their food. the behaviour of the system near the biologically feasible equilibria is thoroughly analyzed. boundedness and dissipativeness of the system are e...

iran has experienced high food prices in recent years. this paper examines the welfare impacts of rising major food groups' prices on iranian urban households using quadratic almost ideal demand system (quaids) approach. the elasticity coefficients derived from quaids are used to estimate compensated variations (cv).the study uses iranian household expenditure and income survey (heis) raw data,...

Abstract The basis of people’s livelihoods is formed depending on food security within the global system economic security. It should be noted that one most important conditions stability to a variety internal and external influences, which may political or nature. One priority areas for achieving in significant part countries process stimulating development national agriculture. Of course, thi...

Modern agriculture is heavily dependent on fossil resources. Both direct energy use for crop management and indirect energy use for fertilizers, pesticides and machinery production have contributed to the major increases in food production seen since the 1960s. However, the relationship between energy inputs and yields is not linear. Low-energy inputs can lead to lower yields and perversely to ...