ali hossein samadi

Infection with COVID‑19 has resulted in considerable mortality all around the world. This study aimed to investigate the effect of convalescent plasma on the treatment of hospitalized patients with COVID‑19 in Imam Khomeini Hospital at Ardabil, Iran.

In this quasi‑experimental clinical trial, patients over 18 years of age with polymerase chain reaction‑positive COVID‑19 were admitted based on the clinical criteria of respiratory distress with hypoxia (O2 saturation <90) and tachypnea (R Relative Risk (RR) >24) with moderate‑to‑severe lung involvement and in the 1st week of respiratory disease who were not intubated were nonrandomly assigned to two groups: convalescent plasma therapy (CPT) group (197 cases) and control group (200 cases). We used the Chi‑square, t‑test, Fisher’s exact test, and Pearson’s correlation coefficient for statistical analysis.

Analyses revealed that length of stay in hospital was significantly lower in the CPT group as compared to the control group (P = 0.001). Twenty‑four cases (22.0%) in the CPT group and 85 cases (78.0%) in the control group needed intubation. Furthermore, mortality was 17 cases (18.3%) in the CPT group and 76 cases (81.7%) in the control group, the difference of which was also found to be statistically significant (P < 0.05).

It seems that CPT can be used as an alternative treatment at the early stages of COVID‑19 to prevent the progress of the disease, reduce the need for intubation and consequently the length of stay in hospital, and finally, decrease mortality

The unstable state of macroeconomic indicators such as gross domestic product (GDP), investment, and inflation rate, as well as the disproportionate level of high volume of cash held by private individuals versus the low volume of liquidity in manufacturing firms, have always been a significant problem in Iran's economy. In this respect, the relationship among the stock market, bank deposits, and speculation in the foreign exchange market, and also, the central bank's role in directing liquidity between them to affect the macroeconomic indicators are important. The current study evaluates this subject for 1988–2018 using a system of simultaneous equations and the three-stage least squares (3SLS) method. The findings indicate that there has been a significant negative relationship among the stock market, bank deposits, and foreign exchange speculation. The stock market and bank deposits have had a significant positive effect on investment and GDP, and in contrast, foreign exchange speculation has shown a significant negative impact. Conversely, bank deposits have negatively impacted the consumer price index (CPI), whereas foreign exchange speculation has shown a substantial direct effect. Finally, despite the existence of a significant negative relationship between three financial markets in the Iranian economy confirmed by the obtained results, the central bank has forfeited a considerable portion of its potential effectiveness in directing liquidity between parallel financial markets to affect nominal and real economic indicators due to interest rate repression.

The purpose of this paper is to investigate the effect of the industry sector tariff rate changes on the Iranian households’ welfare under the conditions of the resistance economy. To achieve this goal, based on Samadi et al.'s (2019) survey, the computable general equilibrium model of Decallo et al. (2013) has been adjusted. After making the adjustments, using the adjusted social accounting matrix of 2011 and GAMS software, the equations were solved and analyzed in the form of three scenarios. The findings show that in the first scenario, without assuming the implementation of the notified policies of the resistance economy, the reduction of tariff rate in all sectors of industry causes the level of households’ welfare will become negative. In the second scenario, assuming the implementation of the notified policies of the resistance economy, welfare in all sectors of industry except medium-tech industries is positive and its trend is descending in all sectors except high-tech industries. In the third scenario, assuming the strengthening of social and institutional factors, welfare in all sectors is positive and its trend is upward in medium and high-tech industries and downward in low-tech industries. Therefore, the reduction of tariff rate is recommended only in the high-tech industries if the notified policies of resistance economy are implemented.

Recently, sustainable development and policy on improving the quality of the environment have attracted economists. The use of fossil fuel tax and subsidies to research and development are among the tools that can reduce air pollution by creating economic incentives and relative price adjustments. In this regard, the present study uses a Computable General Equilibrium (CGE) model to examine environmental impacts, the effectiveness and economic implications of using these two tools. The results show that both instruments reduce the air emissions and social costs of air pollution, while the tax effect was more efficient. Taxation of energy consumption leads to a reduction in consumption indicators, investment types, and welfare. By paying subsidies to the R&D, and resulting increase in investment in R&D, a decline rate in consumer expenditure and physical investment were observed. The welfare increases at a low rate of subsidy and decreases at higher rates.

This paper studied the impact of the most important factors affecting on volatility of GDP in Iran by using Dynamic Stochastic General Equilibrium (DSGE). Furthermore, it is important to understand the contribution of each of the factors to create volatility in GDP. To this end, we introduced institutional quality in production function. In our model, oil price shock is assumed to affect macroeconomics variables through affecting on productivity. The paper applied the model in Iran economy for the period of 1989-2014. The results indicated that one structural break had taken place in GDP in 2007:3 and Gross domestic product volatility has increased in the period after the structural break. The reason for this structural break can be found in the rise in oil prices that began in 2004 and continued for several consecutive years. We also found that the share of factors that affect volatility in GDP has changed after structural break. The variance decomposition indicates that volatility in GDP is most affected by the oil price and the monetary policy shocks. Besides, their share increases after the break point. The share of oil price shocks before the structural break was about 28 percent, but the share rose to 35 percent after the structural break.

One of the most important economic sectors emphasized in resistive economy policies is the value added and production sector. Economic institutions can influence value added by increasing technology spillover and productivity. The purpose of this paper is to investigate the effect of resistive economy policies on the value added of various economic sectors. In order to achieve this goal, the Decalou et al. Model (2013) has been modified and the effect of the resistance index on the technological spillover and production function has been investigated. The main question is how does the resistive economy policies affect the added value of economic sectors? To answer this question, we use a general equilibrium model and GAMS software. The results of the first scenario indicate that in the absence of enforcement policies, value added in agricultural, service and other sectors decrease, but positive changes are observed in industry, oil and gas and mining sectors. In the second scenario, the results show that with the improvement of the economic institutions due to implementation of the resistive economy policies, value added in all sectors would increase. Therefore, it is suggested that the improvement of the institutional status of the economy be considered alongside the implementation of these policies.

In recent years, the causes of double-digit inflation in the economy of Iran have been the biggest challenge for Iranian researchers. However, time inconsistency has been paid less attention while according to Kydland and Prescott (1977), time inconsistency of monetary policy can be the most important cause of inflation bias.
A policy is time inconsistent or dynamic inconsistent when it is considered as the best policy for particular time in the future, but it does not remain so, when that particular time actually arrives. There are two possible mechanisms that have been considered for such a time inconsistency. (i) Strotz(1955-1956) explain that time inconsistency is because of changing preferences, (ii) Kydland and Prescott(1977) consider another explanation that is based on agent’s rational expectation. The main idea is, when people expect low inflation, central bank thinks of high inflation. If people understand it, they predict higher inflation. In this situation, predicted inflation is optimal inflation. In other word, while inflation policy is optimal at first, high inflation policy will be optimal in the end. We use the second mechanism in this paper. Barro and Gordon (1983) have explained time inconsistency of monetary policy as follow: in a discretionary regime, central banker can print more money and make more inflation than people’s expectation. Benefits of this surprising inflation might provide more economic activities or reduce government’s debt. However, if people, due to their rational expectation, understand it and adjust their expectations with it, then policy maker will not reach his target at all. Besides that, due to increased money supply, the level of prices will grow.
So the question that arises here is how much of the inflation is due to discretionary behaviors in applying monetary and fiscal policies? In other words, what is the inflationary bias caused by the Time Inconsistency of monetary and financial policies?
In the present study, the framework of Barro-Gordon has been applied to calculate the inflation bias of time inconsistency of monetary and fiscal policies. In fact, we have extended Walsh (2010)’smodel by adding fiscal variable. These models consist of two main sections: loss function and the supply curve. According to the structure of the economy of the developing countries, the fiscal and monetary policies are dependent and are determined by a third person (the president). Thus, a general loss function which consists of fiscal and monetary variables is used. In fact, the lack of independence of the central bank is considered in this model.
What distinguishes this study from other studies, include: Calculating the inflation bias using a model that considers the time inconsistency of monetary and fiscal policies simultaneously.
Unlike Surico (2008), we used symmetric loss function.
Calculating inflation bias in Each Economic Development plan of Iran
The model solution will be done by two approaches of discretion and commitment. After applying the optimization, inflation bias will be the difference of results of these two approaches. Moreover, the inflationary bias of the model is calculated based on Iran’s economy data over the period of 1991-2016. This bias is then calculated for each of the country's five-year economic development plan.
The results show high inflation bias in Iran (9.8%). Furthermore, based on the results, the first and the third economic development plans have the lowest and the highest inflation bias, respectively. Besides that, it can be seen, predicted inflation in third and second part of fifth economic development plans, have significant difference with performance inflation. In other words, the present model has failed to provide an adequate estimate of the inflation of these two periods. It seems that the reason is considering high target inflation in two plans.

In this paper, we study the effects of demographic transition on government expenditure and Income distribution for Iran’s economy during 1969-2011 using threshold cointegration technique. The results, shows that the year 1986 is the break date of demographic transition. Therefore the whole period is divided into two regimes, 1969-1986 and 1987-2011. The main results of this paper is that, there is a threshold cointegration between demographic transition, government expenditure and income distribution. So, there is long-term equilibrium relationship between them. But, there isn’t any short-term relationship between them. Also, the results of the estimation of error correction model show that adjustment of short-term equilibrium to long-term equilibrium is faster in the second regime rather than the first one.

Based on sustainable development approach, the paper, intends to offer a conceptual framework to evaluate the structure of Iran’s economy. As findings of the paper proves, the maximum and minimum figures of the sustainable development in Iran, respectively belongs to 1970s and 1990s. Also, Sensitivity analysis model indicates that the water issue was the most critical matter within the context of sustainable development in 1990s and even the optimized indicators of water consumption and per capita thereof, as well as the underground water resources have the most influence on improvement of sustainability indicators.

The main purpose of this paper is study the effects of budget deficit shock on the current account deficit in the presence of output shocks in Iran's economy. Moreover, the impacts of budget deficit shock on the exchange rate, GDP shock on the budget deficit and the current account deficit are also analyzed. To achieve these goals, we have used a Vector Autoregressive Model (VAR), Impulse response functions and Variance decomposition. In estimation, we have utilized four variables as budget deficit, current account, GDP and real exchange rate. The results of effect of GDP shock on the budget deficit and current account deficit indicate a negative relation between these two deficits. In other words, the phenomenon of "twin divergence" has been verified. On the other hand, in both cases, the government revenue and the government expenditure shocks on the components of current account, the phenomenon of "twin divergence" weakly has been verified.

This study investigates the effects of oil revenues management on macroeconomic performance in Iran. «Spend- as –you- go» strategy then the «Gradual –Scaling-up» Strategy as a counterfactual one. For this purpose، We have used Iran’s data economy during 1344-1390 (1965-2011) and employed a New Keynesian Dynamic Stochastic General Equilibrium (NKDSGE) model. Based on the first strategy، government allocated all oil revenues surplus obtained from the long run trend to the current and reconstructive expenditures. The findings of the first strategy illustrate that، fluctuations in oil revenues، decreases public and private investments. As a result، we have a reduction in production and economic growth. Moreover، the effective consumption، which is a combination of private and government consumption expenditure، as public goods، declines. The cause of this problem is waste in public expenditure. Based on the second strategy، known as counterfactual strategy، government reserves the oil revenues’ surplus and invests the returns of these reserves in reconstructive activities، gradually but consistently. Based on the second strategy، even with the fluctuation in oil revenues، production boosts due to persistence and continuance of government and private investments. Furthermore، effective consumption and inflation increase. As a whole، the results show that in the second counterfactual strategy; i. e. gradual –Scaling-up، The Oil fund acts as a buffer against decline in oil revenues.

In recent years, in addition to conventional sources of gas, production from unconventional sources is also possible. Iran as a second-largest conventional gas reserves in the world and the fourth producer, intends to enter the gas competition, increase its share in the global gas trade. The purpose of this study is to investigate the long-term exploration, extraction and production of gas and the impact of unconventional gas production. To achieve this objective, System Dynamics approach is used. The model developed consists of three sub-system conventional gas exploration and production cycle, investment and global demand and for the period 2001-2035 is simulated. Model validity is approved and simulation results indicated that, with current trends, the life of undiscovered gas reserves in Iran from 400 years to less than 30 years will be reduce in 2035. Gas production rising from 100 BCM in 2001 to more than 500 BCM in 2035. In other words, the gas production in Iran will be about 5 times over a period of 35 years. Applying scenarios such as increasing the rate of exploration, increased investment in development and increase investment in technological improvements will lead to an increase in gas production. However, the development of unconventional gas could reduce demand security of gas in world and reduce the Iranian gas production in a long-term period. At the same time taking into account all scenarios can increase gas production and thus offset the decline in production is due to the expansion of gas production from unconventional sources.

Main purpose of this study is to identify the effect of tax coefficients on food and drinking industrial structure during 2008-2012 and the impact ofthem on industry monopoly power. To achieve of this purpose, Panel Data regression and data in four digit ISIC are used. The finding indicated that increase of tax coefficient has an inappropriate impact on food and drinking industrial structure in the form of increasing monopoly power of firms. This subject confirms the Schumpeterian view.

Simultaneous variations between world oil price and food prices leads to stimuli scientists to investigate the effect of raising oil price on food prices. The main purpose of this paper is to examine the effect of oil price volatilities on the food price index for the 1990-2006 periods in Iran. To achieve this goal، a vector auto-regression (VAR) model، impulse response function and a auto-regressive distributed lags (ARDL) model have used. The results of impulse response function show that oil price volatilities have no effect on food prices in Iran.. Moreover، results from ARDL model implies that there is no significant relationship between oil price and food prices in the short term and long term. This result may be due to subsidies paid by the government to energy section that prevent any price changes.

The main purpose of this paper is, to design a dynamic model for evaluation of economic and tax policies on Iranian tax system by using system dynamics approach. For this purpose, we consider the tax effort, tax capacity and tax evasion subsystems. The simulation of this model has been accomplished during 2008-2025. The results of base model simulation show that, if current situation continues, situation of tax effort and tax evasion will not in good position and in 2025, only 66 percent of expected tax will be collected. Also the extent of tax evasion in years of the final simulation will be 35 percent. For study of necessary conditions in order to access to optimal status, different scenarios have been designed and simulated. The results of simulations show that, in order to access to the desired status, in addition to coordination and interaction among the variables, some attempts should be done simultaneously to reduce the inflation rate, increase welfare, and decrease the activities in underground economy, increase population growth, per capita revenue and taxes (taxes on consumption and import).

The main objective of the present study is to estimate the size of tax evasion in the economy of Iran. The present study applies the multiple indicators; multiple causes (MIMIC) methodology in Iran economy for the period between 1970 and 2007. The results show that the size of tax evasion has fluctuations during 1970 and 2007 and the size of tax evasion is increasing. The results show that tax burden، the size of government، taxpayers’ income، inflation rate and unemployment rate are the main causes of extension of tax evasion in Iran. The most important causes of tax evasion، which lead to the high extension of tax evasion، are the size of government، tax burden and taxpayers’ income.

The effect of government spending on private consumption، as the largest and the most stable component of aggregate demand always has been preoccupying many economists. In this article، using the elasticity of substitution concept، we investigate the substitutability of government spending for private consumption in 48 OIC countries. We use the Pesaran’s CD test for investigating the cross-section dependency in the data. Then the stationary of variables confirmed by IPS and CIPS tests and the regression equations estimate by CUP-FM estimator. According to the estimation results، the substitutability between government spending and household consumption was confirmed for OIC countries. In addition، the results of estimating tell that in case of countries with larger governments the degree of substitutability between government spending and private consumption is greater.

This study investigates Iran’s stock market by a non-Gaussian distribution function. To estimate this distribution function، Bayesian methods and Markov chain Monte Carlo simulation technique is used. Tehran stock market daily data during August 23، 2002 to February 19، 2011 has been analyzed in this study. The results confirm the existence of a non-Gaussian distribution with a right skewness and fat tail sequence. Therefore، an unexpected crisis in the Iran stock market could not be ignored. The results also confirmed the hypothesis of asymptotically stable Distribution.

This paper studies the validity of Wagner law in selected OIC (Organization of Islamic Conference) member states by classifying them based on their income levels and degrees of corruption. For doing so، the Pesaran Cross-sectional Dependency (CD) test، cross-sectional augmented ADF (CADF) as well as Wasteland and Edgerton''s panel co integration tests have been employed. To estimate the coefficients، the continuous-updated and fully modified (CUP-FM) estimator has been used. The results confirm validity of Wagner law in all economies، having different income levels and corruption degrees.

Agricultural sector as one of the main economic sectors of Iran has a great share in total GDP. The, present study, aims to examine the effects of financial repression policies on capital productivity in agricultural sector. In doing so, we use time series data during 1953-2007 and Gregory – Hansen Cointegration and DOLS methods. Results show that financial repression has no effect on productivity of capital in Iran’s agricultural sector in the long-run. Capital stock and non financial saving both show positive effect on capital productivity in agricultural sector.

The main purpose of this paper is to analyze the determinants of financial development and testing the Simultaneous (trade and financial) openness hypothesis in Iranian economy during 1971-2006. For the analysis procedure, the time series econometrics techniques and the GMM method are applied. The results show that:1-For larger financial development, government should open trade and financial market, simultaneously.2-The effect of trade openness on financial development is greater than financial openness.

Granger and Newbold (1974) proposed the idea of spurious regression in econometrics. They showed that with I(1) dependent and independent variables, if a regression model is estimated by OLS method, the results may be spurious. This idea is extended to variables with different order of integration. In this paper, we review the literature of spurious regression and show that when the variables have different order of integration, for example I(1) & I(2), and I(1) & I(0), the spurious results may occur.

The main purpose of this paper is analyses the short and long run relationship between budget deficit and trade deficit in some MENA countries. The data cover the period from 1971-2000 (and for I.R. IRAN 1959-2003).The relationship between these variables will be analyses in short and long run by using Johansen co-integration tests, ECM, and Granger causality test. The empirical evidence provides support to the view of Ricardian Equivalence in Iran (Islamic Rep.), Jordan, Kuwait, Morocco, Oman, and Tunisia. But, the empirical evidence proves the validity of Keynesian proposition (conventional view) only Egypt, Bahrain, Oman, and Turkey.

The main purpose of this paper is to analys the short and long run relationship between budget deficit and trade deficit, import and export, and Government revenues and expenditures. Also sustainability condition of trade deficit and budget deficit is examined. For doing so, we apply the time series econometrics techniques. The results show that to over come the budget deficit and trade deficit, the Government should, in the short run, decline budget deficit. In order to do this, we recommended that it has to decrease the taxes and increase the domestic deposits. We could not find any cointegration relationship between government revenues and expenditures, export and imports, and two deficits.

In this paper, we analyze the long –run relationship between inflation and Total Factor Productivity (TFP) in the Iranian economy during 1338-1380. For this purpose, we use Gregory –Hansen (1996) Cointegration test. Our Study proceeds at the following steps. 1. We set up a multivariate model for the analysis of the long-run relationship between inflation and Total Factor Productivity (TFP)2. We test the unit root properties of data, and the long-run relationship between variables in the presence of structural breaks.3. We estimate endogenously the break point data.Our results from cointegration tests and dynamic ordinary least square estimator show that there is a negative relationship between inflation and productivity.