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The aim of this study is to make an inventory of the fauna of the Odonata in Theniet El Had National Park, which helps managers to make appropriate decisions for the conservation of these species. The site is entirely forested (Cedrus and Quercus species) with numerous intra-forest natural environments (clearings, grasslands, rocky habitats, springs, pools and ponds, etc.), this mosaic of habitats harbours a remarkable wealth of fauna and flora. Our study focused on the natural and artificial temporary forest ponds, scattered throughout the park, which are of biological and ecological interest for a very wide range of insects, most notably the hemimetabola. These are characterised by a larval stage that is quite different from the adult stage in terms of habitat and lifestyle, namely odonates, where the larvae are aquatic whereas the adults have an aerial life. The inventory of odonates was carried out through monthly surveys of 8 water bodies (7 forest ponds and one hill reservoir) during one year, from March 2017 to February 2018. This preliminary inventory allowed us to inspect 240 individuals of odonates belonging to 18 species i.e. 11 genera and 5 families. The species recorded at the end of this study are the subject of a cartographic representation showing their distribution at the local scale (in the park) and at the national scale.

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Molecular phylogenetic reconstruction of the suborder Zygoptera based on sequences of the nuclear ribosomal gene 18S and mitochondrial gene COI was carried out using species collected from India. Sequence samples of 19 species belonging to 7 families of Zygoptera were used for the analysis. All the existing family levels in Zygoptera were confirmed as monophyletic clades in both analyses. While the 18S analysis resolved deep relations well, the COI analyses supported recently diverged clades. The analysis based on the COI gene showed the monophyly of families Coenagrionidae, Calopterygidae, Lestidae, Chlorocyphidae, and Platycnemididae and was found as a distinct clade. The remaining families Platystictidae and Euphaeidae were polyphyletic to the former clade showing more genetic divergence. In the 18S analysis, from the common ancestor, a monophyletic clade of Coenagrionidae, Platycnemididae, Lestidae and Chlorocyphidae evolved. Euphaeidae, Platystictidae and Calopterygidae were polyphyletic.

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We aim in this study to increase our knowledge of the Odonata in the Aures, an unexplored region of northeastern Algeria, using single-species occupancy model (spOccupancy R package) coupled with spatial interpolation technique (kriging ArcGis) to assess the relationships between elevation and odonatan species distribution. From time windows of about 90 days (June to August 2021), a total of 22 odonatan species belonging to 2 suborders (Anisoptera and Zygoptera) have been recorded in 15 sampling wet biotopes; among them the endangered Calopteryx exul. Our modelling shows that 62% of the odonatological community has a uniform probability of being present in the studied area. The probability of detecting a species is similar during each survey for 90% of the odonatological community except for the endangered Calopteryx exul (p ˂ 0.05) and Crocothemis erythraea (p ˂ 0.05). We also found that Ischnura graellsii and I. saharensis are the most common species; they are predicted to occur in more than 60% of sites, followed by Anax imperator, Orthetrum chrysostigma, and Platycnemis subdilatata, where they occur in about 50% of the wet biotopes sampled. Finally, our modelling revealed no evidence for a significant altitudinal variation (500 to 1900 meters above sea level) impact on both occupancy and detectability of the majority of the odonatan species, except for Crocothemis erythraea and Sympetrum fonscolombii. The kriging interpolation indicates that they are concentrated within the altitude range of 400 m to 1000 m.

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Ramsey model is one of the most important basic models to study intertemporal resource allocation. This model is derived from microeconomic optimal principle so it has a key role in macroeconomics with micro foundations. Hence, in many economic researches it is considered as a reference theory. Application of this model in economy of Iran will provide an appropriate theorem framework for explaining empirical facts of the Iranian economy and will introduce a new approach to researchers. The main idea of this study is generalizing Ramsey model through including terms of trade and its calibration in the economy of Iran. For this purpose first, the model is explained. Then, the first order condition is derived and mathematical optimal path of variables is solved.  Finally, the model is calibrated by GAMS package for economy of Iran in time period (2006-2036). The results indicate that there is a feasible solution for model and the optimal path of variables can be observed. The optimal path of Gross National Production and Consumption are increasing but the optimal path of capital stock and investment is primarily increasing then decreasing. In the final section of this paper a sensitivity analysis is presented. Some scenarios are designed for the important parameters of model like time preferences rate, intertemporal substitution elasticity of consumption, labour growth rate and output elasticity of capital. Sensitivity analysis shows that output elasticity of capital and labour growth rate increased the social welfare and shifted optimal path of variables upward. But time preferences rate and intertemporal substitution elasticity of consumption had inverse effect on social welfare and optimal path of variables.

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Tax reform as a part of financial system’s reforms constitutes the core of fiscal policies and economic adjustment process. The widening tax base and rationalizing tax rates are main priorities in this regard. This paper aims to calculate optimal commodity tax rates and marginal cost of social welfare resulting from indirect taxes in Iran. The calculation of marginal cost of social welfare requires determining the own and cross price elasticities of demand and optimal tax rates for goods and services. These parameters are obtained by estimating demand function of ten good and service groups in a linear expenditure system. This system is estimated through seemingly unrelated regression method using data of ten expenditure deciles of urban households in Iran during 1996-2010. The optimal tax rates are calculated using Ramsey method in a multi-person world and Bergson-Samuelson's social welfare function. In this model, a social welfare function is maximized with respect to given tax revenue of government using Lagrange method. Results show that when social inequality aversion parameter is zero, optimal tax rates almost are equal. By increasing this parameter, which fairness rather than efficiency is considered, these rates are diverged, in a way that some commodity groups are entitled to get subsidy. In addition, as social inequality evasion parameter increases, the marginal cost of social welfare resulting from change in commodity tax rates decreases, and welfare loss gets very small in the highest social inequality evasion rate. So, decreasing subsidy among all good and service groups receiving subsidy, and increasing tax on other groups lead to decrease in social welfare.  

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The aim of this study is to investigate optimal monetary and fiscal policies for the Iranian economy considering Ramsey problem.  Using a Dynamic Stochastic General Equilibrium model, the effects of imposing various taxes such as consumption tax, capital income tax, labor income tax and profit tax are examined by different scenarios. The results indicate that Friedman’s rule, or zero inflation is determined as optimal monetary policy under scenarios with and without price rigidities. In addition, since the governments try to minimize the distortions from taxes levied on different economic sectors, necessity of a subsidy or negative tax is confirmed under Ramsey conditions. According to the findings, the inflation rate not only depends on nominal and real rigidities assumed in the model, but also to the number of instruments available to the Ramsey planner.

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The overall objective of the present paper is demonstrating the utility of price forecasting of farm prices and validating the same for major crops namely, Paddy, Ragi and Maize in Karnataka state for the year 2016 using the time series data from 2002 to 2016. The results were obtained from the application of univariate ARIMA techniques to produce price forecasts for cereal and precision of the forecasts were evaluated using the standard criteria of MSE, MAPE and Theils U coefficient criteria. The results of ARIMA price forecasts amply demonstrated the power of the ARIMA model as a tool for price forecasting as revealed by pragmatic models of forecasted prices for 2020. The values of MSE, MAPE and Theils U were relatively lower, indicating validity of the forecasted prices of the three crops.

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The purpose of this study is to investigate the impact of adding a non-Ricardian household to a DSGE model in choosing the Ramsey optimal monetary policy and consequently the effects on macroeconomic variables (such as output gap, consumption gap, inflation, and rising nominal exchange rate). Therefore, after estimating a model for the Iranian economy, the Ramsey optimal monetary policy was selected from 6 monetary policy alternatives. Then, in two scenarios, a non-Ricardian household is added to the model. In the first scenario, the non-Ricardian household consists of 20% of households and in the second, it consists of 40% of households. Then, Ramsey optimal monetary policy was selected for these two scenarios. The results show that the when the percentage of non-Ricardian households in the model increases, monetary policy-maker deviates from targeting monetary variables and gives more importance to production targeting. Second, if Ramsey optimal monetary policy is chosen without considering the non-Ricardian household in the model, in facing the shock of falling oil prices, the shock of declining money demand and the shock of rising external inflation, the responses of the production and consumption sectors in scenarios 1 and 2 are significantly different from the baseline model. But the consumption and production sectors have almost the same reactions in three models in response to the shock of the rising nominal exchange rate.