the economy's dependence on oil revenues and derivatives of these products make the country's economy heavily influenced by the volatility and instability of the pricing of these products. therefore, it seems necessary to develop non-oil exports. this paper examines the causality relation and the effect of foreign direct investment, economic openness and real exchange rate on non-oil ...

the purpose of this research was to study the role of non-governmental organization inpreserving of urban green areas in the city of tehran. this is a descriptive-correlationresearch method. population of this study was 120 active members of two non-governmentalorganizations in tehran. after distributing the questionnaires, 62 questionnaires werereturned. content and face validity of the instru...

We present a new method to represent variable bindings in the Warren Abstract Machine (WAM), so that ages of variable bindings can be easily found using this new representation in our intelligent backtracking schema. The age of a variable bound to a non-variable term will be the youngest choice point such that backtracking to that choice point can make that variable an unbound variable again. I...