oil sector is the most effective sector in these countries. oil is the most important product that world industries use as the cheapest energy. the price of oil depends on the world’s supply and demand and many economic, political and geographical variables. this is the reason why the price of oil has fluctuations. the fluctuations in oil price lead to fluctuate in the oil revenues of the membe...

the subject of monetary policy orientation and tailoring a framework within which the credibility and desirability of the policies and the policy makers is enhanced, while the most important goal of policies, i.e reaching to and preserving a low and stable inflation rate is achieved, has recently been a controversial issue for a large number of economists. in fact the necessity arised since the...

  Propagation of dust ion acoustic waves in plasmas composed of nonthermal distributed electrons and stationary dust particles is investigated. Nonlinear Schrdinger equation is derived to describe small amplitude waves, using the reduction perturbation technique. Modulation instability of dust ion acoustic waves is analysed for this system. Parametric investigation indicates that growth rate of...

1. introduction thunderstorms or lightning storms are kinds of storms that generally are associated with the convective clouds and usually are resulted in hailing, strong winds, and flash floods. clouds of convective storms are observed in most regions, but a small percentage of the convective storms can produce severe weather conditions and flash floods that cause damages. a flash flood is a d...

Purpose: The Identification of Functional Ankle Instability (IdFAI) questionnaire is a valid and reliable tool to identify ankle instability, but this questionnaire is written in English and Persian speakers have difficulties in using it. Therefore, this study aimed to translate the IdFAI questionnaire in Persian and evaluate its validity and reliability. Methods: The present study is a non-ex...

Birth interval is one of the major determinants of the fertility rate. In this paper structural change approach is used to study the instabilities in the effects of different socio-economic factors on birth intervals of children with respect to couple's years of marriage factor in Ahvaz-Iran. A class of M-fluctuation tests for parameter instability is used and based on these tests different evi...