Radon is a naturally occurring radioactive gas and a major indoor contribution of exposure to ionizing radiation in dwellings. 222Rn is a health hazard gas what is responsible for thousand lung cancer deaths every year. In this study, indoor radon concentrations present in thirty representative houses in Mahallat city, Iran, were determined in order to estimate lung cancer risk associated with residential radon exposure. Long-term passive method, using CR-39, was used to measure the radon concentration. The results showed an association between the age of the dwellings and the indoor radon concentration that was found, in that the concentration of radon tended to increase as the age of the dwelling also increased. The indoor radon concentrations were calculated to be within the range of 23±2 to 350±26 Bq․m . By taking into consideration the EPA recommendation and ICRP statement, the average annual risk of lung cancer from inhaled radon was calculated as 0.09%, 0.06%, 0.01%, and 0.03% for current smokers (CS), those who had ever smoked (ES), never smokers (NS) and the general population, respectively.

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Quick changes in international economy have made it by far more difficult and more complicated to plan to work in foreign markets than it was in the past. Actually, with regard to the high intensity of competition in the area of world trade, it is unavoidably inevitable to accept the role of thoughts, skills and abilities of managers of commercial units to enter world markets. With respect to the importance of the issue, we are dealing with lack of applicable studies investigating the effective characteristics of management on the performance of firm in the area of international trade in the developing countries in general and in Iran in particular. Thus, the present essay intends both to recognize the managerial characteristics effective on the development of non-petroleum exports in Iranian firms exporting such products, and to analyze the hypotheses related to the issue.

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