a design discharge is an important issue in the design process of pressurized irrigation networks. underestimating the desing discharge affect, the required pressure and offtake discharge, increase the cost of the network. because of the lack of a standard and reliable method for this propuse, usually different approches are used by designers. the network fails to provide the required flow rate...

despite controversy, the contingent valuation method (cvm) is widely used for non-market valuation. among elicitation methods of cvm, the dichotomous choice (dc) has been paid attention. there are two types of dc methods: single-bounded dc (sbdc) and double-bounded dc (dbdc). dbdc is more efficient than sbdc. many of cvm studies in iran used dbdc but data analyses were done by logit model; that...

hydraulic simulation of water flow in irrigation canals may reveal management shortcomings and help managers find solutions to them. hydraulic simulation models can be appropriate tools for understanding hydraulic behavior of irrigation systems. in the present study, the steady state hec-ras model was tested and compared with the mike 11 unsteady state model. a secondary irrigation canal in the...

Background and objectives: Birth spacing is an important variable for identification of fertility acceleration, total fertility rate, and maternal and fetal health. Therefore, special attention has been paid to this issue by researchers in the fields of medical sciences, health, and population. In addition, proper analysis of this concept is of foremost importance. Application of classical anal...

a confounder is a variable whose presence affects the variables being studied so that the results do not reflect the actual relationship. there are various ways to exclude or control confounding variables including randomization, restriction and matching. but all these methods are applicable at the time of study design. when experimental designs are premature, impractical, or impossible, resear...