نشریه مطالعات اقتصاد بخش عمومی
سال دوم شماره 2 (پیاپی 4، تابستان 1402)

The history of cryptocurrency began in 2008 as a way of payment. However, cryptocurrencies have evolved into a complex ecosystem of high-yielding speculative assets. Unlike traditional financial instruments, these currencies are not mainly traded in organized and law-abiding locations, but on online platforms where anonymity prevails. In fact, facilitating financial transactions without the presence of intermediaries such as banks and financial institutions can be considered one of the goals of creating virtual money. The purpose of this research is to investigate the effects of Bitcoin as the largest digital currency before (16/08/2015 to 16/11/2019) and after the Covid-19 pandemic (17/11/2019 to 26/02/2022) on Other digital currencies and gold. One of the components of this analysis is the identification of selected digital currencies that have had the greatest impact from the price bubbles and the fall of the price of Bitcoin, as well as the investigation of the origin of the investment of digital currencies and gold. The results show that among digital currencies, Bitcoin, as a representative of the digital currency index, has the most spillover effects on Litecoin, Ethereum, and Dash, and has the least spillover effects on Dogecoin and Ripple. Also, as an investable asset, gold is a safe haven for investment, because it is less aligned with volatile assets like Bitcoin compared to other digital currencies. Based on the results of the current research, the bubbles in the digital currency market show the irrationality of the market, and due to the existing spillover effects, they may spread to the domestic financial markets and cause a lot of fluctuations. 

Tax is one of the most important sources of revenue for governments and one of the political tools to improve the distribution of income. In this regard, it is important and valuable to evaluate the reaction of various types of tax income to economic growth in order to know the country's tax capacity. This  research, by applying the quantile regression approach and Nonlinear Autoregressive Distributed Lag  and using the statistical evidence of Iran over 1981-2019, shows that in high tax quantiles, the positive effect of economic growth on taxes has increased in all types of taxes. Also, considering that goods and services tax has the highest share in tax revenues, its low tax elasticity can greatly reduce the stability of government revenues. But direct taxes, income tax and salary tax, due to their higher elasticity, play an important role in the stability of the government's income, the confirmation of the symmetrical effects of positive and negative economic growth shocks on all types of taxes shows that the tax is low compared to the potential capacity. Tax and the inability of the tax system to implement the tax efficiently. Therefore, focusing on the development of activities with high added value and taxes with higher elasticity will play an important role in the stability of the government's income.

Economic sanctions are a common diplomatic tool for countries to pursue political demands abroad or to punish non-aligned countries. Economic sanctions have been criticized for failing to achieve their goals and negatively impacting areas such as human rights, democracy, poverty, health care and basic living conditions. Sanctions imposed on Iran have affected various aspects of the economy, in terms of consumption, revenue, production, import of goods and services, and so on. This study examines the history and effects of economic sanctions on income inequality in Iran imposed by the United States during the period 1978-2018 using the Distributed Interrupt Autoregression (ARDL) method. Therefore, in this study, changes in oil revenues have been used as an indicator of economic sanctions. The results show that economic sanctions have different effects on income inequality in the short and long term. Also, the variables of foreign direct investment, inflation rate and degree of trade openness have a positive and significant effect on income inequality.

The abundance of natural resources in oil-rich countries has a dual role in the economy of these countries, in such a way that if natural resources are spent in order to improve economic infrastructure, economic growth will increase and otherwise would cause Dutch disease. One of the necessary prerequisties in directing the income stream from the sail of oil is financial development, which can play an important role in directing the income from the use of natural resources toward high added value. So the main objective of study was to investigate the effect of financial development on the natural resource market of Mena countries. in order to achieve the objectives of this study, the statistics of Mena countries (14 selected countries) during 2000-2020 and econometric approach of generalized method of generalized method are used. The results showed that financial development has a negative and significant effect on the rent of natural resources, energy consumption and share of agricultural products, so the effect of efficiency prevails over the effect of scale and effective financial development can provide the basis for dynamic economic growth. Industrialization has a positive and significant effect on the natural gas rent and the share of agricultural sector and negative effect on per capita energy consumption. therefore, the more the share of industry in gross domestic product increases, energy consumption per person decreases and natural resources rent has increased due to increased demand for efficient exploitation of natural resources. urbanization has a positive and significant effect on the share of agricultural products and energy consumption per capita and has no significant effect on natural resources rent. Therefore, directing toward high value added activities in the form of effective financial development, utilization of urban scale and industry development based on new technology are the most important factors for reducing the vulnerability of this group of economies.

Among the energy exporting countries, Iran is among the largest countries in terms of the share of gas and oil reserves. In the meantime, due to the reliance of this country's economy on the income from energy exports, the topic of energy security and its effects on various economic and social dimensions has always been a topic of discussion among policymakers. Energy security means easy and cost-effective access to various energy sources, which plays an important role in achieving economic goals and development of countries. Therefore, in this research, considering the importance of energy trade, it analyzed the effect of energy security index on gas export in a case study of Iran using the fully modified ordinary least squares method (FMOLS) in the period from 1997 to 2020. The findings of the study show that there is no significant relationship between gas energy security index and its export. In addition, the results show that GDP and exchange rate have a positive effect on gas export, while population density has a negative effect on this variable. Based on the findings of this study, it can be argued that moving towards reducing the dependence of the country's economic growth on the income from the energy sector is the most important pillar of strengthening energy security. On the other hand, strengthening regional ties and expanding commercial exchanges can play a significant role in improving the energy security situation and reducing the effects of sanctions.

Earning sustainable revenues is one of the most important issues for organizations to perform their activities and pursue their goals. In management and economics literature, cash flow and revenue stream are said to act as blood circulation in the body of an organization. It is certain that without having sustainable revenues, no organization, even charity ones, can continue working effectively. Thus, it is significant and required to deal with the subject of generating sustainable revenues in Mashhad Transportation and Traffic Organization, located in Iran. The present research aimed at identifying sustainable revenues development strategies in Mashhad Transportation and Traffic Organization. Qualitative research methods were applied to conduct this study. In order to collect the data, in-depth interviews were held with local experts in Mashhad, Tehran and Isfahan, and also with Iranian experts working in traffic organizations in the US, Canada, Denmark, all of whom were specialized in economics, civil management and transportation and traffic. Moreover, extensive Internet searches were performed to provide theoretical literature and fundamentals and specifically to identify and follow sustainable revenue development strategies used in traffic organizations of other cities in the world and also in traffic park activities in Finland, Turkey, China and India. This research study also applied the observation method in visiting traffic parks and in brainstorming sessions held to develop new ideas and strategies.The data analysis was performed by using interview content analysis, and through classifying and analyzing the data collected from the Internet.