abstract the present research accomplished to determination of the trade liberalization effects on import function of iran’s wheat crop using time series data from 1357 to 1387 that earn from sources such as agricultural and aerology statistics annual letter, customhouse and iran central bank website.in this investigation, at first, wheat liberalization index was measured by using level of inte...

Characterization and evaluation of a biological submerged filter was carried out on a full-scale pilot plant performing removal of biochemical oxygen demand (BOD) and total nitrogen (TN) from pre-treated urban wastewater. The average influent values of BOD5, chemical oxygen demand (COD) and TN were 370, 1,015 and 60 mg/L, respectively. The pilot plant produced good discharge quality during stea...

in a structural time series regression model, binary variables have been used to quantify qualitative or categorical quantitative events such as politic and economic structural breaks, regions, age groups and etc. the use of the binary dummy variables is not reasonable because the effect of an event decreases (increases) gradually over time not at once. the simple and basic idea in this paper i...

Two-thirds of education production function studies relating learning to school and parental inputs also include parental income. This confounds demand and production functions, since in demand functions income determines the school inputs used in the production function. In a comprehensive review of the literature, we show that with this misspecification significantly positive school input coe...