introduction: given its low and sparse precipitation both in spatial and temporal scales, iran is nestled in an arid and semiarid part of the world. on the other hand, because of population growth, urbanization and the development of agriculture and industry sector is frequently encountered with increasing water demand. the increasing trend of water demand will widen the gap between water suppl...

Integrated crop–livestock (ICL) systems are diverse production that can improve resource utilization through spatially or temporally rotating land among crop, livestock, and pasture uses. However, research on whether the enhanced translates to greater crop productivity is still warranted. A field experiment was initiated at South Dakota State University in 2016 determine impacts of integrating ...

We use the sub/supersolution method to analyze a semipositone Dirichlet problem for the p-Laplacian. To find a positive solution, we therefore focus on a related problem that produces positive subsolutions. We establish a new nonexistence result for this subsolution problem on general domains, discuss the existence of positive radial subsolutions on balls, and then apply our results to problems...

Let E be a complete, separable metric space and A be an operator on Cb(E). We give an abstract definition of viscosity sub/supersolution of the resolvent equation λu − Au = h and show that, if the comparison principle holds, then the martingale problem for A has a unique solution. Our proofs work also under two alternative definitions of viscosity sub/supersolution which might be useful, in par...

The base of this review is to consider the relevant role that animal factors (potential milk yield, body weight, body condition score, state of lactation, parity and fertility) play on milk performance (considering the energy balance and the rumen function across the full lactation curve of animals) and milk quality (milk protein content, milk fat content, milk lactose content, vitamins, minera...

Assessments of the efficiency grazing systems, in terms productivity and ecological sustainability, are necessary view increased demand for animal protein. In this study, methane (CH4) emissions (sniffer methodology), dry matter (DM) yield, paddock chemical composition (AOAC Van Soest methods), nutrient intake (dry matter, DMI; crude protein, CPI; metabolizable energy, MEI), daily milk yield (D...

The Beverton-Holt theory of harvesting a multicohort fishery subject to constant recruitment, and the Leslie matrix harvesting model modified to include a nonlinear stock-recruitment relationship, are extended and shown to be related through the ultimate-sustainable-yield problem for an age-structured population. The well-known result that the optimal harvesting policy for the Leslie matrix mod...

Promoting indigenous submerged macrophytes is considered an important measure to restore shallow lakes. On the other hand, dense stands of aquatic vegetation often cause nuisance for boating, swimming and by obstruction of water flow. Consequently, the interests of recreational users may conflict with nature conservation. At first sight, aiming lake management at intermediate vegetation biomass...

In this paper, we established the exploitation of impulsive harvesting single autonomous population model by Logistic equation. By some special methods, we analysis the impulsive harvesting population equation and obtain existence, the explicit expression and global attractiveness of impulsive periodic solutions for constant yield harvest and proportional harvest. Then, we choose the maximum su...