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Showing 15 results for Javaheri
Volume 1, Issue 1 (NO. 1- 2011)
Abstract
One of the most important issues that organizations face is how to motivate employee to perform their roles well, thus ensuring that organization to retain its effectiveness. Indeed, specific set of employees' behaviors, discretionary ones that employees perform for organization that can significantly affect on organization’s success specifically. These behaviors are called organizational citizenship behaviors, defined as discretionary work behaviors that that have not been recognized directly or explicitly by the formal reward system, and in the aggregate, they promote the functioning of the organization. In this study has tried to investigate relationships between organization ethical values, organizational justice, organizational commitment, ethical behavior and organizational citizenship behaviors in Staff part employees of Payam Nour University (Tehran branch). In respect to purpose, this study is applied and in respect to doing method and data collection, is descriptive-analytic. LISREL and structural equation model were used for testing the hypotheses. The results of this study indicated that organization ethical values positively affects on procedural and distributive justice. Procedural and distributive justice positively affects on organizational commitment. Also organizational commitment positively affects on ethical behavior. Ethical behavior positively affect on sportsmanship and altruism dimensions of organizational citizenship behaviors.
Volume 12, Issue 46 (Summer 2019)
Abstract
Metalepsis, in its narratological sense, is a trope in which an unnatural relationship is built between different levels of narrative. The natural relationship between narrative levels is formed by the act of narrating; a character from one level becomes the narrator of another. The term “Metalepsis of topic and illustration” can be coined to name a similar trope. This trope has been used for centuries in Persian poetry. Every Image comprises a topic and an illustration. The topic is what is being talked about and the illustration is what the topic is compared to. When several images are present along together, two different levels are distinguishable: the level of the topic and the level of illustration. The natural relationship between these two levels is similarity and any other relationship will result in metalepsis. As in the narratological metalepsis, there is always a paradox in the metalepsis of topic and illustration. The effect of these two kinds of metalepsis is also similar and can be humorous, fantastic, or a mixture of the two.
Volume 13, Issue 2 (summer 2013 2013)
Abstract
Traditional approach to the firm size and its growth rate is based on comparative statics analysis and it does not really deal with the dynamics of growth. This paper takes a dynamic approach to investigate the relationship between firm size and its growth rate for Iranian insurance firms during 2003-2009. The study applies two ways to verify the validity of Gibrat's law in Iranian insurance industry. First way is to consider the independence of two important attributes of firms including firm size and growth rates. The second way is based on panel regression estimation. The results of the study reject the validity of Gibrat’s law and indicate the fact that small firms grow faster than their larger counterparts.
Volume 13, Issue 2 (5-2022)
Abstract
The aim of this study is to analyze the role of phonological opacity in the phonetic representation of the prefix of progressive aspect in Kermanshahi Persian. In this dialect, when the progressive prefix /mi-/ is added to the verb stem, it changes in form in certain cases, depending on the nature of the first vowel of the verb. In Kermanshahi Persian, the progressive prefix is added to the left side of verbal root - which is, in turn, followed by verbal ending. This research is based on the Optimality Theory-Candidate Chains (McCarthy, 2007) - a version of Serial Optimality Theory. The data of this research have been collected through the conversations with the speakers of Kermanshahi Persian dialect in two age groups of over fifty- and under twenty-year-olds, relying – as well - on researchers' language intuition. The results of this study indicate that what causes the opacity in the phonetic representation of the vowel of progressive prefix in Kermanshahi Persian dialect is the occurrence of counter-bleeding interaction. The Serial Optimality Theory, is more successful in explaining this phenomenon than Parallel Optimality Theory.
1. Introduction
Kermanshahi Persian is a dialect which is spoken in the city of Kermanshah mainly in the west of Iran, and it presents certain linguistic differences with Standard Persian. One of the morpho-phonological differences is in the phonetic form of the progressive prefix /mi-/ when attached to certain verbal stems. Like what occurs in Standard Persian with the subjunctive prefix /be-/, the vowel of the prefix /mi/ undergoes vowel harmony if the following verbal stem contains a round vowel, and just as in /be-ro/ ("Go!") which surfaces as [bo-ro] on the phonetic level, /mi-/ in Kermanshahi Kurdish turns into [mo-] if there is a round element in the verbal stem, making forms like [mo.-ko.n-am] (meaning 'I do') out of /mi-kon-am/. The motivation of the such rule, however, is challenged by the phonetic form [mo.-xɑm] (I want), in which the vowel of the prefix is rounded, but there does not seem to be any round element as the motivation. This opaque application of the phonological process is analyzed in this article via the principles Optimality Theory. The main questions of the present study are as follows: (1) to what extent is Optimality Theory successful in explaining the opacity introduced by Kermanshahi Persian data? (2) What are the relevant active constraints? (3) In what permutation must the constraints be organized? (4) Which of the two versions of Optimality Theory, namely Parallel or Serial, is more successful in the explanation of the data in this study?
2. Literature Review
In order to prepare the grounds and to have a better insight into the present study, the review is based on the relevant works on phonological opacity and Optimality Theory which have been done inside and outside Iran.
2.1. International Studies
Bermúdez-Otero (1999, pp. 36-39) is among the first researchers who reported the challenge which the first versions of OT were faced with regarding the opacity phenomenon, and he asserts that the difficulty lies in OT neglecting the intermediate forms between the phonological and phonetic levels. This claim is also supported by McCarthy (2007, p.99), who reports the necessity of considering derivational path of the phonological processes. Urek (2013, p.1), too, reasons that Parallel OT fails to explain opacity since the Generator in this theory is designed to produce the candidates in one attempt. Anttila (2006, p. 893-901) classifies the suggested solutions to the problem of opacity in OT in three sets: "Input-Output Correspondence" theory which was first put forth by Benua (1995, pp. 77-82); "Sympathy Theory" suggested by MacCarthy (1999, 2000); and "Opacity Approach" put forward by Goldrick (2000, p.16). Alqahtani (2020, p. 22) is among the recent researchers who has investigated opacity as the result of counter-bleeding by analyzing examples from colloquial Persian. Also, Hauser and Hughto (2020, p. 29) claim that the general solution to opacity in OT could be found in what they call "contextual faithfulness constraints".
2.1. Iranian Studies
Many optimality-theoretic studies have been conducted in Iran on Persian and Kurdish data, among which one can mention those of Bijankhan (2006), Modarresi Ghavami (2011), Heidarpor Bidgoli (2012) in Persian; and Naqshbandi (2011), Fattahi (2012), Zahedi (2014), and Mohammadi (2014) in different dialects of Kurdish. As valuable as these studies are, none deals with the problem of opacity in Optimality Theory.
3. Methodology
The data in the present study have been collected in two ways: (1) through interviews with Kermanshahi Persian speakers of two age groups of above fifty and below twenty. The first group was chosen for their tendency towards using this dialect in their daily conversations, and the younger group was chosen as speakers who lean towards Standard Persian for its social prestige. This study, though, does not aim to investigate linguistic variations of these two age groups, but rather tries to identify the alternating forms in the verbal forms with progressive aspect. (2) through linguistic intuition of the researchers of the study, who are themselves, native speakers of Kermanshahi Persian. The collected data were then transcribed and the relevant alternating forms were identified. The last step was to identify the underlying phonological forms in order to decide on the nature and direction of the changes.
4. Discussion and Results
The following table illustrates the alternating forms of the progressive prefix in Kermanshahi Persian.
Table 1
The Alternative Forms in Progressive Prefix of Kermanshahi Persian Dialog
| (1) | mi.-bi.n-am prog. – see – 1S "I see." |
(2) | mi.-xɑ.n-am prog. – read – 1S "I read." |
|||
| (3) | mi.-bu.s-am prog. – kiss – 1S "I kiss." |
(4) | mi.-ka.n.-am prog. – dig – 1S "I dig." |
|||
| (5) | mi.-ʃu.r-am prog.- wash – 1S "I wash." |
(6) | mi.-ke.ʃ-am prog.-pull-1S "I pull." |
|||
| (7) | mo.- xor.-am prog.-eat-1S "I eat." |
(8) | mi.- sɑ.z –am prog.-make-1S "I make." |
|||
| (9) | mo.- ko.ʃ- i prog.-kill-2S "You kill." |
(10) | mo.- ko.n- am prog.-do-1S "I do." |
|||
| (11) | mo.- xɑ- m prog.-want-1S "I want." |
(12) | mo.- wo.r -am prog.-cut-1S "I cut." |
|||
| * prog.: progressive – 1S: first person singular – 2S: second person singular | ||||||
/mi-xwɑ/ --(vowel rounding)à moxwɑ --(the omission of glide w)à[moxɑ]
If the glide omission, which is motivated by cluster simplification, was applied earlier than vowel rounding, the process of vowel rounding would be bled by it, leading to the incorrect phonetic form of *[mi-xɑ]; but since the actual order is in the opposite direction, the order of vowel rounding and glide omission is that of counter-bleeding, which causes opacity.
As was cited by many studies in the review section, parallel OT seems unable to choose correct opaque forms, the same is proved about Kermanshahi Persian data.
Tableau 1
Inability of Parallel Optimality Theory to explain Opacity Phenomenon
| Ident (r) | Aligh-left(r) | mi-xwɑ-m |
| * | a. mixwɑm | |
| * | b. moxwɑm | |
| Mc. mixɑm | ||
| * | d. moxɑm | |
| Notes: symbol M shows an incorrect winning candidate. - Aligh-left(r) constraint penalizes any candidate with no agreement in rounding - Ident (r) penalizes any candidate with a changed value in the feature [round] | ||
Optimality Theory-Candidate Chains, in addition to valuing the intermediate steps and derivational paths, enjoys a new form constraint that guarantees a fixed order of the application of the processes, namely Prec(A,B), in which constraint B is only violated if constraint A has been violated earlier. We can consider Prec(Ident(r),Max(r)) to penalize any candidate in which: (a) the round element is deleted without the process of vowel rounding having occurred earlier; (b) the round element is deleted and the vowel rounding occurs following that. With this constraint at play, we can consider the steps of derivation as depicted by the following tableaux.
Tableau 2
The First Step of Derivation
| Ident (r) | Max (r) | No-Codaprg | Prec(Id,Max) | Complex-Syll | Align-l(r) | mi-xwɑ-m |
| * | * | Fa. mox.wɑm | ||||
| * | *! | b. mi.xɑm | ||||
| * | *! | c. mix.wɑm | ||||
| * | *! | d. mox.wɑm | ||||
| Notes: Complex-Syll penalizes any candidate in which there is consonant cluster in a syllable - No-Codaprog penalizes any form with a coda in the same syllable as the progressive prefix- Max (r) penalizes any candidate in which a round segment has been deleted (compared with the input) | ||||||
The Second Step of Derivation
| Ident (r) | Max (r) | No-Codaprog | Prec(Id,Max) | Complex-Syll | Align-l(r) | mox.wɑm |
| * | Fa. mo.xɑm | |||||
| *! | b. mo.xwɑm | |||||
| *! | c. mox.wɑm | |||||
| * | * | *! | d. mix.wɑm |
Tableau 4
The Third Step of Derivation and the End of Cycle (Convergence)
| Ident (r) | Max (r) | No-Codaprog | Prec(Id,Max) | Complex-Syll | Align-l(r) | mo.xɑm |
| Fa. mo.xɑm | ||||||
| *! | b. mo.xwɑm | |||||
| *! | c. mox.wɑm | |||||
| *! | d. mi.xɑm |
In Serial Optimality Theory, which OT-CC is a version of, the Generator is only allowed to produce candidates with one difference from the input. The winner chosen by the Evaluator will then be given to the same tableau, and there again, the Generator produces candidates with only one difference from the new input. This cycle will continue until the winner is the same form as the input – a step which is also called as convergence. This success in choosing the right form as the final winner is all thanks to the gradualness of Serial OT and the Prec constraint, which disqualifies the threatening competing forms Parallel OT was not able to shed out of the competition.
6. Conclusion
Optimality Theory-Candidate Chains proves to be more successful in the case of opacity observed in Kermanshahi Persian progressive prefix than the Parallel version of OT, where the process of choosing the final winner is not gradual and the intermediate forms are not taken into account due to the Generator's permission to produce candidates with any number of differences compared to the input. The gradual nature of OT-CC along with the Prec constraint leads to the choice of the right candidate as the winner. The following tableau, also known as Harmonic Improvement tableau, shows how the winners of the later rounds incur less threatening violations.
Tableau 5
The Harmonic Improvement in [mo.xɑm]
| Ident (r) | Max (r) | No-Codaprog | Prec(Id,Max) | Complex-Syll | Align-l(r) | |
| * | a. mix.wɑm | |||||
| * | * | b. mox.wɑm | ||||
| * | c. mo.xɑm |
In the tableau above, the candidates are the winners of each step of derivation, with each being more harmonic – incurring fewer violations to the higher-ranking constraints – than the previous candidate.
Volume 18, Issue 118 (December 2021)
Abstract
In this study the influence of Alyssum homolocarpum seed gum (AHSG), basil seed gum (BSG) and different levels of banana peel flour (BPF) (0, 20 and 40%) on physicochemical properties of cakes containing date syrup (DS) or fig syrup (FS) was investigated. Parameters such as batter and cake pH, density, bostwick number, cake crumb and crust color, texture and sensory attributes were determined. The results revealed that increasing the banana peel flour decreased batter and cake pH, baking loss and sensory scores while increased batter and cake density, batter consistency, cake moisture, darkness and hardness. The influence of basil seed gum on moisture retention and consistency improvement was more significant than Alyssum homolocarpum seed gum. However, the cakes incorporated with Alyssum homolocarpum seed gum had lighter color and softer texture. Cakes manufactured by fig syrup had lighter color, softer texture and better organoleptic properties and fig syrup was a better replacer for sucrose in cake formulation.
Volume 18, Issue 119 (january 2021)
Abstract
Abstract
In the present study, the effect of adding quinoa flour and germinated wheat flour on the physicochemical, microbial and sensory properties of sponge cake was investigated.The results showed that as the amount of quinoa flour and germinated wheat flour increased, ash, protein, and fat content of sponge cake samples significantly increased (p<0.05). The lowest porosity was observed in sample T6 (sponge cake containing 15% quinoa flour + 15% wheat flour) (p≤0.05). The highest moisture content was observed in sample T8 (sponge cake containing 15% quinoa flour + 0% germinated wheat flour) on all days (p≤0.05). Texture profile analysis results showed that texture of sponge cake samples significantly increased with increasing amount of quinoa flour and germinated wheat flour (P≤0.05). Evaluation of sensory test results showed that the highest color score belonged to sample T7 (sponge cake containing 0% quinoa flour + 15% germinated wheat flour) and sample T8 (sponge cake containing 15% quinoa flour + 0% germinated wheat flour). Was. The lowest odor score was observed in the control sample and the highest in the sample T8 (sponge cake containing 15% quinoa flour + 0% germinated wheat flour) (p≤0.05). The highest sensory score belonged to the sample T8 (sponge cake containing 15% quinoa flour + 0% germinated wheat flour) and sample T8 (sponge cake containing 15% quinoa flour + 0% germinated wheat flour) was selected as the highest treatment.
Volume 19, Issue 1 (7-2015)
Abstract
To encounter with Knowledge Management, the organizations should select appropriate knowledge strategy and knowledge management strategy. There are different methods for developing these strategies. In this study a System Dynamics model developed to select and integrate both strategies. In the proposed model organizational factors such as business strategy, structure, culture, human resource and IT infrastructure have been considered. On the other hand, from the dynamic approach perspective, the knowledge creation processes and the level of explicit or tacit knowledge have direct impact on selected strategies. In this paper all the stock variable and their initial value have been identified then the flow variable and theier increasing/decreasing rate have been determined and casual loops and stock and flow diagrams was proposed. At last after simulating and testing the dynamic model, different scenarios and policies have been presented for the case study. The results indicate improvement in both KM strategy and knowledge strategy. Keywords: knowledge management, knowledge management strategy, knowledge strategy, system dynamics
Mohammad Javad Taheri Amiri, Ali Ashrafian, Farshid Reza Haghighi, Maedeh Javaheri Barforooshi,
Volume 19, Issue 1 (5-2019)
Volume 19, Issue 1 (5-2019)
Abstract
The construction and maintenance of structural pavement was a high-cost problem in last decade. The mechanical properties of self compacting concrete (SCC) required important factors .From its mechanical properties, the compressive strength (CS) is necessary to investigate experimental and computational intelligence analysis in construction materials. Developing models with accurate estimation for this key property caused to saving costs and time and producing an optimal blend. Because of the many advantages, using of SCC in structures is increasing. Construction of precast-prefabricated components, with the use of concrete has also recently been considered. Concrete properties have significant role in precast-prefabricated girders behavior. Exact prediction of these properties is the base of member’s analysis and design. The main purpose of this study is presents new formulation to estimate the compressive strength of self-compacting concrete containing rice husk ash (RHA) using robust variant of genetic programming, namely gene expression programming (GEP) method. To evaluate the performance of the GEP-based proposed model, prediction was also done using classical data driven methods named artificial neural network (ANN) and multiple linear regression (MLR) models. A large and reliable experimental database containing the results of 156 compressive strength of SCC incorporating RHA is collated through an extensive review of the literature. The performance of proposed models of CS is then assessed using the database, and the results of this evaluation are presented using selected performance measures. New expressions for the estimation of CS of SCC are developed based on the database. To evaluate the modeling performances of the proposed GEP models for CS, different statistical metrics were used. Correlation coefficient (R), root mean square error (RMSE), mean absolute error (MAE) were used as the measure of precision. The results showed that the models developed using the aforementioned methods have accuracy over 90 percent in prediction of CS of SCC. The results of testing datasets are compared to experimental results and their comparisons demonstrate that the GEP model (R=0.94, RMSE= 4.308 and MAE=4.916) outperforms ANN (R=0.92, RMSE= 5.136 and MAE=5.624) and MLR (R=0.89, RMSE= 8.212 and MAE=9.472). Proposed models have a strong potential to predict compressive strength of self compacting concrete incorporating rice husk ash with great precision. The importance of different input parameters is also given for predicting the compressive strengths at various ages using gene expression programming. Performed sensitivity analysis to assign effective parameters on compressive strength indicates that cementitious binder content is the most effective variable in the mixture. The assessment results present that the performance of the proposed models are in close agreement with the experimental results. Moreover, the new GEP-based formulation provides improved estimates of the compressive strength of SCC compared to ANN and MLR models. The proposed design equation can readily be used for pre-design purposes or may be used as a fast check on deterministic solutions.
Volume 23, Issue 2 (summer 2023)
Abstract
Aim and Introduction
In recent decades, the environment has become one of the most important concerns of societies and governments. Achieving economic growth and development is costly and leads to an increase in the consumption of ecological capital. The efforts of countries to increase per capita income and prosperity, if not accompanied by environmental considerations, will bring irreversible losses, including rapid climate change and environmental destruction. Thus, comprehensive investigation and determination of economic and non-economic effective factors on the environment is of particular importance, to the extent that it has forced governments to adopt short- and long-term policies and programs to protect the environment.
The existing economic literature on the Environmental Kuznets Curve (EKC) hypothesis indicates that at a threshold level of per capita income, countries reach a level of development where environmental improvements are achieved, but these studies have a serious flaw. Because they only focus on GDP per capita as a key variable to achieve environmental improvements and ignore the social dimension which is considered the pillar of sustainable development. Since the human development index includes the simultaneous description of social development and economic development, therefore, in this research, the Human Development Index is used instead of GDP per capita to investigate the Environmental Kuznets Curve (EKC) hypothesis and the relationship between HDI and the quality of the environment. Furthermore, political institutions can have a long-term direct impact on the environment and its sustainability. Therefore, investigating whether the indicators of human development, political and civil liberties can affect the quality of the environment, can be important.
Method
In the present study, the effects of human development, political and civil liberties indicators on the environmental performance index (Ecological Footprint) in developing countries and developed countries are investigated using the System Generalized Method of Moments method (GMM-SYS). Then the Environmental Kuznets Curve hypothesis is investigated in selected countries. Likely, a country that has benefited from more ecological capital for its needs in the past will be more prone to environmental destruction and use of ecological resources in the future. Therefore, it is necessary to investigate the impact of the variable interruption of the ecological footprint on its value in the current year. Accordingly, in this research, the method of the System generalized moments is used, which helps to solve the possible problems of endogeneity caused by the existence of an interval of the ecological footprint variable as an independent variable by using instrumental variables.
The Generalized Moments' estimator is used in cases where the independent variables of the model are not completely exogenous. This estimator controls for the endogeneity problem by using instruments from the intercept of the dependent variable or the intercept of any other endogenous variable that is assumed to be uncorrelated with the fixed effects. The validity of the tools used in the model can be measured using the j-Hansen (1982) and Arellano and Bond AR (2) tests.
Findings
The results of the research indicate that the Human Development Index in selected developing and developed countries has a significant and negative effect on the ecological footprint, and a higher human development index is useful for improving the quality of the environment and reduces of pollutant emissions. Therefore, when the level of income, education, and health services in a country improves, the awareness of the importance of a safe and quality environment will increase. Similarly, according to the results of the Kuznets hypothesis, the relationship between the Human Development Index and the ecological footprint in the studied countries, confirms the hypothesis of Kuznets and the inverted U.
The index of political development and civil liberties has a negative and significant effect on the ecological footprint in both developing and developed countries. It seems that the increase in civil liberties, higher democracy, and improvement of political rights will reduce the damage to the environment.
The results suggest that with the increase in the consumption of fossil fuels, more pollutants are released into the environment, which leads to the destruction of the environment and harming it. Based on the results of the research, it can be said that trade liberalization and active international trade allow the transfer of newer technologies to developing countries that produce fewer pollutants. In addition, increasing urbanization in developing countries has a negative impact on the quality of the environment, but countries that focus more on economic development and scale can improve the quality of the environment by promoting the use of advanced technologies in parallel with urbanization.
Discussion and Conclusion
The findings of the research indicate that policymakers are more likely to achieve sustainable economic development by improving the level of the human development index. Therefore, providing education and a health care system for all members of society can lead to the reduction of environmental degradation through the improvement of the human development index; Thus, increasing democracy, clarifying laws and regulations, freedom of assembly, freedom of the media and awareness can control corruption and prevent the personal use of natural and environmental resources by officials and powerful people.
Policies such as pollution tax, green tax, development of energy-saving vehicles, and replacing them with worn-out vehicles can reduce energy consumption and reduce the emission of pollutants in the environment. Furthermore, increasing the degree of trade openness allows the entry of advanced and improved technologies that produce less pollution. Therefore, policymakers in developing countries are advised to import clean and renewable energy technologies to their country by increasing active international trade.
Keywords: Human Development Indicator, Political Development Indicator, Ecological Footprint, Environmental Kuznets Curve (EKC) Hypothesis, Systemic Generalized Method of Moments
JEL Classification: F18, O13, P28, P48, Q56
In recent decades, the environment has become one of the most important concerns of societies and governments. Achieving economic growth and development is costly and leads to an increase in the consumption of ecological capital. The efforts of countries to increase per capita income and prosperity, if not accompanied by environmental considerations, will bring irreversible losses, including rapid climate change and environmental destruction. Thus, comprehensive investigation and determination of economic and non-economic effective factors on the environment is of particular importance, to the extent that it has forced governments to adopt short- and long-term policies and programs to protect the environment.
The existing economic literature on the Environmental Kuznets Curve (EKC) hypothesis indicates that at a threshold level of per capita income, countries reach a level of development where environmental improvements are achieved, but these studies have a serious flaw. Because they only focus on GDP per capita as a key variable to achieve environmental improvements and ignore the social dimension which is considered the pillar of sustainable development. Since the human development index includes the simultaneous description of social development and economic development, therefore, in this research, the Human Development Index is used instead of GDP per capita to investigate the Environmental Kuznets Curve (EKC) hypothesis and the relationship between HDI and the quality of the environment. Furthermore, political institutions can have a long-term direct impact on the environment and its sustainability. Therefore, investigating whether the indicators of human development, political and civil liberties can affect the quality of the environment, can be important.
Method
In the present study, the effects of human development, political and civil liberties indicators on the environmental performance index (Ecological Footprint) in developing countries and developed countries are investigated using the System Generalized Method of Moments method (GMM-SYS). Then the Environmental Kuznets Curve hypothesis is investigated in selected countries. Likely, a country that has benefited from more ecological capital for its needs in the past will be more prone to environmental destruction and use of ecological resources in the future. Therefore, it is necessary to investigate the impact of the variable interruption of the ecological footprint on its value in the current year. Accordingly, in this research, the method of the System generalized moments is used, which helps to solve the possible problems of endogeneity caused by the existence of an interval of the ecological footprint variable as an independent variable by using instrumental variables.
The Generalized Moments' estimator is used in cases where the independent variables of the model are not completely exogenous. This estimator controls for the endogeneity problem by using instruments from the intercept of the dependent variable or the intercept of any other endogenous variable that is assumed to be uncorrelated with the fixed effects. The validity of the tools used in the model can be measured using the j-Hansen (1982) and Arellano and Bond AR (2) tests.
Findings
The results of the research indicate that the Human Development Index in selected developing and developed countries has a significant and negative effect on the ecological footprint, and a higher human development index is useful for improving the quality of the environment and reduces of pollutant emissions. Therefore, when the level of income, education, and health services in a country improves, the awareness of the importance of a safe and quality environment will increase. Similarly, according to the results of the Kuznets hypothesis, the relationship between the Human Development Index and the ecological footprint in the studied countries, confirms the hypothesis of Kuznets and the inverted U.
The index of political development and civil liberties has a negative and significant effect on the ecological footprint in both developing and developed countries. It seems that the increase in civil liberties, higher democracy, and improvement of political rights will reduce the damage to the environment.
The results suggest that with the increase in the consumption of fossil fuels, more pollutants are released into the environment, which leads to the destruction of the environment and harming it. Based on the results of the research, it can be said that trade liberalization and active international trade allow the transfer of newer technologies to developing countries that produce fewer pollutants. In addition, increasing urbanization in developing countries has a negative impact on the quality of the environment, but countries that focus more on economic development and scale can improve the quality of the environment by promoting the use of advanced technologies in parallel with urbanization.
Discussion and Conclusion
The findings of the research indicate that policymakers are more likely to achieve sustainable economic development by improving the level of the human development index. Therefore, providing education and a health care system for all members of society can lead to the reduction of environmental degradation through the improvement of the human development index; Thus, increasing democracy, clarifying laws and regulations, freedom of assembly, freedom of the media and awareness can control corruption and prevent the personal use of natural and environmental resources by officials and powerful people.
Policies such as pollution tax, green tax, development of energy-saving vehicles, and replacing them with worn-out vehicles can reduce energy consumption and reduce the emission of pollutants in the environment. Furthermore, increasing the degree of trade openness allows the entry of advanced and improved technologies that produce less pollution. Therefore, policymakers in developing countries are advised to import clean and renewable energy technologies to their country by increasing active international trade.
Keywords: Human Development Indicator, Political Development Indicator, Ecological Footprint, Environmental Kuznets Curve (EKC) Hypothesis, Systemic Generalized Method of Moments
JEL Classification: F18, O13, P28, P48, Q56
Volume 23, Issue 3 (autumn 2023)
Abstract
Introduction
Nowadays, environmental problems, especially air pollution, are one of the major issues in the world's metropolises with increasing its dimensions and side effects. Humans are one of the main sources of air pollution. The age structure of the population is an important indicator in the progress of societies. It can be said that one of the effective factors in economic growth and long-term socio-economic development plans is the age structure of the population (youth or aging population). In working-age (provided that the labor market has the capacity to absorb more workforce in activities), increasing labor supply leads to economic growth.
In general, the age structure of population is important because economic activities and energy consumption vary by age or stage of life. On the other hand, the age of household head is related to household size (people over 65 usually have smaller households than middle-aged people). Studies conducted in Iran have mostly focused on examining Kuznets' environmental hypothesis, the impact of income and population changes on carbon dioxide emissions, and so far have not examined the effect of aging on carbon dioxide emissions. Therefore, this article examines the effect of aging on air pollution in Iran. This article uses the GMM to investigate the dynamic effect of population aging on air pollution during 1981-2020.
Methodology
To collect information for this study, a documentary method was used. The research was conducted based on annual data from 1982 to 2020 in Iran's economy. EViews software was used to estimate the model. It should be noted that data related to research variables were extracted from various sources such as the Central Bank of Iran Statistical Center of Iran, and Energy Balance Sheets.
To estimate the model, a time series econometric method called GMM was used because the model used in this study is dynamic and satisfies generalized moment conditions. In fact, GMM is used for time series models that are linear and also provide generalized moment conditions and instrumental variable properties. This method have many advantages.
Results and Discussion
In this study, the impact of population aging on air pollution was investigated using the GMM in Iran during the period of 1981-2020. The estimation of the model indicates that increasing the age of the population and the transition of the age structure of the population to the aging stage has a negative effect on air pollution. As it is predicted, Iran will face the problem of population aging in the next few years. According to the results, with increasing population, it can be expected that air pollution and environmental degradation will decrease. Due to the negative coefficient of the per capita income squared, the Kuznets environmental hypothesis is confirmed by considering the age structure of the population. In addition, urbanization, industrialization, trade openness, pollution of the previous period have positive and significant effects on air pollution.
The results indicate an inverted U-shaped EKC pattern between environmental degradation (pollution emissions) and per capita income (economic growth); therefore, it can be concluded that environmental degradation initially increases with increasing per capita income in a country, but after reaching a certain level of economic growth, environmental degradation stops and then decreases. Therefore, the results confirm the Kuznets environmental hypothesis for Iran. Based on this, it is recommended that the government design its plans with environmental considerations, especially air pollution. The results indicate that population aging has a significant negative effect on air pollution emissions. Population aging is detrimental to a country's economy and although it is inevitable for any country, policies to increase the number of elderly people in the population mix cannot be formulated and implemented even though it reduces air pollution levels. However, the harm caused by population aging outweighs this benefit. Of course, recently topics such as "active aging" have been raised to deal with population aging logically and should be on policymakers' agenda given the transition of age structure and movement towards aging in future years.
Conclusion
Based on the evidence of Iran's population age distribution during the period under study, it can be said that in future decades, older individuals will make up a higher percentage of the total population. This will lead to a reduction in carbon dioxide pollution automatically without government intervention or any other actions. The results of this study also show that urbanization and industrialization have positive impacts on air pollution. This result indicates that with the increase in the number of industrial enterprises and the trend towards urbanization in Iran, air pollution has increased. The reason for this is that most industries in Iran are energy-intensive and use fossil fuels. Another reason is the outdated technology with low efficiency in production. Other research findings show that pollution from previous periods and trade liberalization have positive effects on air pollution. The policy of economic liberalization by creating division of labor and using advantages, increasing capacity utilization in industries, increasing capital formation rates, changing technology, and creating competition in international markets lead to higher productivity levels for all production factors at a higher level.
Nowadays, environmental problems, especially air pollution, are one of the major issues in the world's metropolises with increasing its dimensions and side effects. Humans are one of the main sources of air pollution. The age structure of the population is an important indicator in the progress of societies. It can be said that one of the effective factors in economic growth and long-term socio-economic development plans is the age structure of the population (youth or aging population). In working-age (provided that the labor market has the capacity to absorb more workforce in activities), increasing labor supply leads to economic growth.
In general, the age structure of population is important because economic activities and energy consumption vary by age or stage of life. On the other hand, the age of household head is related to household size (people over 65 usually have smaller households than middle-aged people). Studies conducted in Iran have mostly focused on examining Kuznets' environmental hypothesis, the impact of income and population changes on carbon dioxide emissions, and so far have not examined the effect of aging on carbon dioxide emissions. Therefore, this article examines the effect of aging on air pollution in Iran. This article uses the GMM to investigate the dynamic effect of population aging on air pollution during 1981-2020.
Methodology
To collect information for this study, a documentary method was used. The research was conducted based on annual data from 1982 to 2020 in Iran's economy. EViews software was used to estimate the model. It should be noted that data related to research variables were extracted from various sources such as the Central Bank of Iran Statistical Center of Iran, and Energy Balance Sheets.
To estimate the model, a time series econometric method called GMM was used because the model used in this study is dynamic and satisfies generalized moment conditions. In fact, GMM is used for time series models that are linear and also provide generalized moment conditions and instrumental variable properties. This method have many advantages.
Results and Discussion
In this study, the impact of population aging on air pollution was investigated using the GMM in Iran during the period of 1981-2020. The estimation of the model indicates that increasing the age of the population and the transition of the age structure of the population to the aging stage has a negative effect on air pollution. As it is predicted, Iran will face the problem of population aging in the next few years. According to the results, with increasing population, it can be expected that air pollution and environmental degradation will decrease. Due to the negative coefficient of the per capita income squared, the Kuznets environmental hypothesis is confirmed by considering the age structure of the population. In addition, urbanization, industrialization, trade openness, pollution of the previous period have positive and significant effects on air pollution.
The results indicate an inverted U-shaped EKC pattern between environmental degradation (pollution emissions) and per capita income (economic growth); therefore, it can be concluded that environmental degradation initially increases with increasing per capita income in a country, but after reaching a certain level of economic growth, environmental degradation stops and then decreases. Therefore, the results confirm the Kuznets environmental hypothesis for Iran. Based on this, it is recommended that the government design its plans with environmental considerations, especially air pollution. The results indicate that population aging has a significant negative effect on air pollution emissions. Population aging is detrimental to a country's economy and although it is inevitable for any country, policies to increase the number of elderly people in the population mix cannot be formulated and implemented even though it reduces air pollution levels. However, the harm caused by population aging outweighs this benefit. Of course, recently topics such as "active aging" have been raised to deal with population aging logically and should be on policymakers' agenda given the transition of age structure and movement towards aging in future years.
Conclusion
Based on the evidence of Iran's population age distribution during the period under study, it can be said that in future decades, older individuals will make up a higher percentage of the total population. This will lead to a reduction in carbon dioxide pollution automatically without government intervention or any other actions. The results of this study also show that urbanization and industrialization have positive impacts on air pollution. This result indicates that with the increase in the number of industrial enterprises and the trend towards urbanization in Iran, air pollution has increased. The reason for this is that most industries in Iran are energy-intensive and use fossil fuels. Another reason is the outdated technology with low efficiency in production. Other research findings show that pollution from previous periods and trade liberalization have positive effects on air pollution. The policy of economic liberalization by creating division of labor and using advantages, increasing capacity utilization in industries, increasing capital formation rates, changing technology, and creating competition in international markets lead to higher productivity levels for all production factors at a higher level.
Volume 23, Issue 4 (winter 2023)
Abstract
Introduction:
The interactions of economies have caused the sensitivity to choose import sources, target markets and trade partners in general. Each country chooses its own trade partners based on its coordinates in order to minimize its import costs and generate maximum export income while avoiding the negative effects of international economic fluctuations. Diversification of trade partners is one of the ways to strengthen of an economy and reduce the vulnerability against international economic fluctuations and shocks. Diversification of import sources and export destinations of each country can lead to the stability of foreign trade and increase the stability of domestic production. In Iran's economy, due to the special conditions, such as economic sanctions, this issue is of double importance. In the previous periods of sanctions (before 2017), one of the weak points of Iran's economy has been the decrease in diversity in the mix of foreign trading partners, which includes the decrease in the number of buyers of oil (as Iran's main export product), the decrease in the arrival of foreign tourists, and the reduction of countries exporting goods to Iran. In this situation, two countries, China and Russia, became Iran's main trade partners, and to some extent, it reduced the impact of Western economic sanctions against Iran's economy. Meanwhile, in the last two decades, China has practically become the main competitor and substitute for the economic powers of the world, known as the OECD member countries, and has acquired large markets in South and East Asia, the Middle East and Africa. Therefore, it can be said that diversification of trade partners for all countries of the world practically means creating opportunities and for Iran, it means a way to survive.
Methodology:
The present research is based on the "Locomotive theory", which expresses the influence and effectiveness of the economic fluctuations of countries on each other through foreign trade. For this purpose, two models with the same structure were designed for two periods during 1970- 2018 to investigate the role of China's presence or absence among Iran's trading partners using the structural vector auto-regression (SVAR) model. According to the "Locomotive theory", international economic fluctuations affect countries through foreign trade, and only a few countries have the potential to bring countries out of the crisis. This theory states that during 1975-77, the United States was the main "locomotive" to pull out the world economy (more precisely, the industrialized countries) from the previous recession (the first oil shock), and paid a very high price for it, and it was necessary for America's major partners in that period, especially Japan and Germany, to accept their role as the locomotive of the world economy and in this way help both the American economy and the world economy. This theory specifically states that industrialized countries are the sources of international economic fluctuations and their prosperity or recession first spreads to major partners and with a delay to other countries.
The monetary and financial policies of the United States have played a decisive role in the development of global economic cycles through trade and financial links with smaller countries. In recent decades, although the importance and role of the United States has remained, but the US economy is not growing fast enough to act as the sole locomotive of the world economy train, especially in the last decade. China alone, and other major emerging markets as a whole, have become important drivers of the global economy. China and other major emerging markets are increasingly interdependent. Because on the one hand, China is the main importer of raw materials, and on the other hand, it is a supplier of manufactured products and foreign investment. The occurrence of such a phenomenon in the field of international economy has attracted the attention of many researchers to discuss the role of business partners and examine the unilateral and mutual effects of such decisions.
According to a study conducted in 2015 by Assoumou Ella for Kenya, the trade relationship between a third world country and industrialized countries is drawn in the presence of an emerging economy. In this research, the same model is used for Iran's economy. For this purpose, in the present study, based on the theoretical and experimental literature of this field a structural vector auto-regression (SVAR) model has been designed and specified. The first reason for using this model is its design based on the theoretical structure, and second reason is to provide a framework in which a variable, while being endogenous, is affected by other endogenous variables; but it should not affect them. The second case is very important regarding Iran's economy; because the macroeconomic variables of Iran's economy for several reasons (weak structure of Iran's economy, the issue of sanctions, customs tariffs) have no significant effects on the macroeconomic variables of trading partners included in the model.
Results and Discussion:
The results of the analysis of the reaction functions show that in most cases, the fluctuations of the macroeconomic variables of Iran (including GDP, inflation, FDI, export and import) have decreased in response to the fluctuations of GDP and inflation of OECD countries after the inclusion of China in the model. So that the intensity of the impact of the shocks entered into the model has become milder and the time for disappearing of the shocks has also been shortened.
Conclusion:
The results show that the diversification of Iran's Trade partners during the mentioned period has reduced the effect of the economic fluctuations of OECD countries on the macroeconomic variables of Iran. This means more stability of Iran's economy, so diversification of trade partners leads to resiliency against international crises, especially in the context of sanctions.
The interactions of economies have caused the sensitivity to choose import sources, target markets and trade partners in general. Each country chooses its own trade partners based on its coordinates in order to minimize its import costs and generate maximum export income while avoiding the negative effects of international economic fluctuations. Diversification of trade partners is one of the ways to strengthen of an economy and reduce the vulnerability against international economic fluctuations and shocks. Diversification of import sources and export destinations of each country can lead to the stability of foreign trade and increase the stability of domestic production. In Iran's economy, due to the special conditions, such as economic sanctions, this issue is of double importance. In the previous periods of sanctions (before 2017), one of the weak points of Iran's economy has been the decrease in diversity in the mix of foreign trading partners, which includes the decrease in the number of buyers of oil (as Iran's main export product), the decrease in the arrival of foreign tourists, and the reduction of countries exporting goods to Iran. In this situation, two countries, China and Russia, became Iran's main trade partners, and to some extent, it reduced the impact of Western economic sanctions against Iran's economy. Meanwhile, in the last two decades, China has practically become the main competitor and substitute for the economic powers of the world, known as the OECD member countries, and has acquired large markets in South and East Asia, the Middle East and Africa. Therefore, it can be said that diversification of trade partners for all countries of the world practically means creating opportunities and for Iran, it means a way to survive.
Methodology:
The present research is based on the "Locomotive theory", which expresses the influence and effectiveness of the economic fluctuations of countries on each other through foreign trade. For this purpose, two models with the same structure were designed for two periods during 1970- 2018 to investigate the role of China's presence or absence among Iran's trading partners using the structural vector auto-regression (SVAR) model. According to the "Locomotive theory", international economic fluctuations affect countries through foreign trade, and only a few countries have the potential to bring countries out of the crisis. This theory states that during 1975-77, the United States was the main "locomotive" to pull out the world economy (more precisely, the industrialized countries) from the previous recession (the first oil shock), and paid a very high price for it, and it was necessary for America's major partners in that period, especially Japan and Germany, to accept their role as the locomotive of the world economy and in this way help both the American economy and the world economy. This theory specifically states that industrialized countries are the sources of international economic fluctuations and their prosperity or recession first spreads to major partners and with a delay to other countries.
The monetary and financial policies of the United States have played a decisive role in the development of global economic cycles through trade and financial links with smaller countries. In recent decades, although the importance and role of the United States has remained, but the US economy is not growing fast enough to act as the sole locomotive of the world economy train, especially in the last decade. China alone, and other major emerging markets as a whole, have become important drivers of the global economy. China and other major emerging markets are increasingly interdependent. Because on the one hand, China is the main importer of raw materials, and on the other hand, it is a supplier of manufactured products and foreign investment. The occurrence of such a phenomenon in the field of international economy has attracted the attention of many researchers to discuss the role of business partners and examine the unilateral and mutual effects of such decisions.
According to a study conducted in 2015 by Assoumou Ella for Kenya, the trade relationship between a third world country and industrialized countries is drawn in the presence of an emerging economy. In this research, the same model is used for Iran's economy. For this purpose, in the present study, based on the theoretical and experimental literature of this field a structural vector auto-regression (SVAR) model has been designed and specified. The first reason for using this model is its design based on the theoretical structure, and second reason is to provide a framework in which a variable, while being endogenous, is affected by other endogenous variables; but it should not affect them. The second case is very important regarding Iran's economy; because the macroeconomic variables of Iran's economy for several reasons (weak structure of Iran's economy, the issue of sanctions, customs tariffs) have no significant effects on the macroeconomic variables of trading partners included in the model.
Results and Discussion:
The results of the analysis of the reaction functions show that in most cases, the fluctuations of the macroeconomic variables of Iran (including GDP, inflation, FDI, export and import) have decreased in response to the fluctuations of GDP and inflation of OECD countries after the inclusion of China in the model. So that the intensity of the impact of the shocks entered into the model has become milder and the time for disappearing of the shocks has also been shortened.
Conclusion:
The results show that the diversification of Iran's Trade partners during the mentioned period has reduced the effect of the economic fluctuations of OECD countries on the macroeconomic variables of Iran. This means more stability of Iran's economy, so diversification of trade partners leads to resiliency against international crises, especially in the context of sanctions.
Volume 24, Issue 1 (1-2022)
Abstract
Systemic Acquired Resistance (SAR) as a management strategy for plant parasitic nematode is a state of resistance increased after a previous infection of plant to a biotic pathogen. Induction of SAR is accompanied by local and systemic enhancement of Salicylic Acid (SA). SA increase in plant is concomitant with PR1 expression. We examined the effect of three chemicals including SA, Abscisic Acid (ABA), and DL-β-Amino-n-Butyric Acid (BABA) on the root-knot nematode Meloidogyne incognita on tomato plants. The expression of PR1 genes and 9-Cis-Epoxycarotenoid Dioxygenase (NCED) as markers for SAR and ABA-related activity genes was investigated in growth chamber conditions. Results showed that all elicitors reduced the population of nematode as compared to the control. Shoot length, shoot fresh and dry weight of nematode infected tomatoes pre-treated with BABA increased by 20, 25, and 8 % and number of eggs, galls, egg masses and reproduction factor decreased by 33, 18, 18, and 20%, respectively. All elicitors increased the expression of PR1 and NCED genes in nematode infected tomato. These data suggest that SA, BABA and ABA activate similar defenses in tomato plants, which is partly SA- and ABA-related. SA, BABA, and ABA pretreated tomatoes infected with M. incognita trigger a SAR-response and lead to the control of the nematode under controlled conditions.
Volume 24, Issue 1 (spring 2024)
Abstract
Economic growth is one of the most common goals in both developed and developing countries. Economic growth affects various economic and social aspects, such as poverty, welfare, unemployment, and inflation. Knowing the factors influencing economic growth is critical for developing countries. Trade of goods and services affects economic growth by increasing national income. On the other hand, nowadays, the world is facing the climate change crisis and its consequences, such as floods, landslides, earthquakes, etc., which can have negative and destructive effects on economic growth. Oil exporting countries have weak export diversity due to single-product trade and are located in the hot and dry orbit of the globe due to their geographical location. The main goal of this study is to investigate the impact of economic complexity as a symbol of international trade and ecological footprint as a symbol of climate change on economic growth in OPEC from 1995 to 2020 and using the method of generalized method of moments (GMM). The results indicate a positive and very significant effect of the economic complexity index on economic growth in oil-exporting countries. On the other hand, the ecological footprint has a negative and significant impact on economic growth in OPEC.
Introduction:
Economic growth and development are main goals in developing countries, because achieving growth and development can increase living standards, increase people's well-being, reduce the level of poverty and unemployment, and consequently strengthen the foundations of governments. Knowing the factors affecting economic growth is one of the critical goals of economic policymakers (Rahimi et al., 2020). In previous studies, much research has focused on the influence of capital, labor, and productivity on economic growth. However, less attention has been paid to other factors. Today, it is clear that export diversification, which is an essential criterion of economic complexity, has a substantial effect on economic growth. On the other hand, the world today is facing climate change, which results from destructive human activities and has very adverse effects on economic growth. Therefore, the main goal of this research is to investigate the effect of economic complexity and ecological footprint on economic growth in OPEC from 1995 to 2020 using the generalized method of moments. In this research, the effect of economic complexity on economic growth in the developing countries of the OPEC organization has been investigated for the first time. On the other hand, in this innovative research, the ecological footprint variable was used to proxy climate change.
Methodology:
There are two methods for estimating model in dynamic panel data. The basic premise of GMM is called the first-order differential method. By imposing some changes to the first-order differential GMM method, the orthogonal deviation GMM method was obtained. In this research, both one- and two-step methods have been used to prevent single effects. Two tests are proposed to ensure the appropriateness of using this method for estimating the model. Initially, the Sargan test is used to demonstrate the validity of instrumental variables. The second test includes the first-order correlation test AR (1) and the second-order AR (2).
Results and Discussion:
The economic complexity index (ECI) in all three models with fixed effects, single-stage GMM, and two-stage GMM has a positive and significant effect on economic growth in OPEC. A one-unit increase in the economic complexity index increases the economic growth of OPEC by 0.028 units in the fixed effects model, 0.032 units in the single-stage GMM, and 0.154 units in the two-stage GMM. The ecological footprint (EF) index in three mentioned models has a negative and significant effect on economic growth in OPEC. A one-unit increase in the ecological footprint index causes a decrease of -0.013 units in the model with fixed effects, -0.038 units in the single-stage GMM, and -0.087 units in the two-stage GMM. The labor force (L), as the main variables of the Solo growth model, has a positive and significant effect on economic growth in OPEC in all models. A one-unit increase in the labor force index causes economic growth by 0.029, 0.028, and 0.055 in models with fixed effects, one-stage GMM, and two-stage GMM, respectively. Gross fixed capital, which is used as capital (K) in this study, has a positive and significant effect on economic growth in OPEC in all three models. A one-unit increase in capital causes an increase in the economic growth of OPEC by 0.017 units in the model with fixed effects, 0.054 units in the single-stage GMM, and 0.163 units in the two-stage GMM, respectively. Productivity of production factors (T), which is also used as technology in some research, has a positive and significant effect on economic growth in OPEC so that a one-unit increase in productivity of production factors causes an increase in economic growth by 0.009, 0.044 and 0.072 units, respectively in the model with fixed effects, single-stage GMM and two-stage GMM.
Conclusion:
The results of the present study showed that in all three fixed effects models, one-stage GMM and two-stage GMM, the economic complexity index has a positive and significant effect on economic growth in OPEC. With the increase in economic complexity, countries' knowledge, technology, and innovation in producing various goods and services will increase. As a result, exports and economic growth will be positively affected. On the other hand, the economic complexity index, in addition to creating a positive effect on quantitative indicators, has a positive effect on qualitative indicators, including the quality of human resources, innovation, savings, and increasing productivity, which can again increase economic growth. On the other hand, in all three models of fixed effects, one-stage GMM and two-stage GMM, the ecological footprint index significantly negatively affects economic growth in OPEC. An increase in the ecological footprint index means the increase in the use of all the planet's natural resources to meet a country's needs, including food, clothing, housing, etc. With the increase in the use of land resources and in the long-term time horizon, the climate change crisis can increase. With the increase in floods, global warming, landslides, and other natural disasters, economic growth will be negatively affected.
Introduction:
Economic growth and development are main goals in developing countries, because achieving growth and development can increase living standards, increase people's well-being, reduce the level of poverty and unemployment, and consequently strengthen the foundations of governments. Knowing the factors affecting economic growth is one of the critical goals of economic policymakers (Rahimi et al., 2020). In previous studies, much research has focused on the influence of capital, labor, and productivity on economic growth. However, less attention has been paid to other factors. Today, it is clear that export diversification, which is an essential criterion of economic complexity, has a substantial effect on economic growth. On the other hand, the world today is facing climate change, which results from destructive human activities and has very adverse effects on economic growth. Therefore, the main goal of this research is to investigate the effect of economic complexity and ecological footprint on economic growth in OPEC from 1995 to 2020 using the generalized method of moments. In this research, the effect of economic complexity on economic growth in the developing countries of the OPEC organization has been investigated for the first time. On the other hand, in this innovative research, the ecological footprint variable was used to proxy climate change.
Methodology:
There are two methods for estimating model in dynamic panel data. The basic premise of GMM is called the first-order differential method. By imposing some changes to the first-order differential GMM method, the orthogonal deviation GMM method was obtained. In this research, both one- and two-step methods have been used to prevent single effects. Two tests are proposed to ensure the appropriateness of using this method for estimating the model. Initially, the Sargan test is used to demonstrate the validity of instrumental variables. The second test includes the first-order correlation test AR (1) and the second-order AR (2).
Results and Discussion:
The economic complexity index (ECI) in all three models with fixed effects, single-stage GMM, and two-stage GMM has a positive and significant effect on economic growth in OPEC. A one-unit increase in the economic complexity index increases the economic growth of OPEC by 0.028 units in the fixed effects model, 0.032 units in the single-stage GMM, and 0.154 units in the two-stage GMM. The ecological footprint (EF) index in three mentioned models has a negative and significant effect on economic growth in OPEC. A one-unit increase in the ecological footprint index causes a decrease of -0.013 units in the model with fixed effects, -0.038 units in the single-stage GMM, and -0.087 units in the two-stage GMM. The labor force (L), as the main variables of the Solo growth model, has a positive and significant effect on economic growth in OPEC in all models. A one-unit increase in the labor force index causes economic growth by 0.029, 0.028, and 0.055 in models with fixed effects, one-stage GMM, and two-stage GMM, respectively. Gross fixed capital, which is used as capital (K) in this study, has a positive and significant effect on economic growth in OPEC in all three models. A one-unit increase in capital causes an increase in the economic growth of OPEC by 0.017 units in the model with fixed effects, 0.054 units in the single-stage GMM, and 0.163 units in the two-stage GMM, respectively. Productivity of production factors (T), which is also used as technology in some research, has a positive and significant effect on economic growth in OPEC so that a one-unit increase in productivity of production factors causes an increase in economic growth by 0.009, 0.044 and 0.072 units, respectively in the model with fixed effects, single-stage GMM and two-stage GMM.
Conclusion:
The results of the present study showed that in all three fixed effects models, one-stage GMM and two-stage GMM, the economic complexity index has a positive and significant effect on economic growth in OPEC. With the increase in economic complexity, countries' knowledge, technology, and innovation in producing various goods and services will increase. As a result, exports and economic growth will be positively affected. On the other hand, the economic complexity index, in addition to creating a positive effect on quantitative indicators, has a positive effect on qualitative indicators, including the quality of human resources, innovation, savings, and increasing productivity, which can again increase economic growth. On the other hand, in all three models of fixed effects, one-stage GMM and two-stage GMM, the ecological footprint index significantly negatively affects economic growth in OPEC. An increase in the ecological footprint index means the increase in the use of all the planet's natural resources to meet a country's needs, including food, clothing, housing, etc. With the increase in the use of land resources and in the long-term time horizon, the climate change crisis can increase. With the increase in floods, global warming, landslides, and other natural disasters, economic growth will be negatively affected.
Volume 24, Issue 4 (Winter 2024)
Abstract
Aim and Introduction
Making changes in the tax system is one of the basic and important needs for increasing government tax revenues. To achieve this, the tax system must move in a direction that increases the tax base. One of the most important solutions can be reducing tax exemptions and deductions. Since tax deduction plays an important role in determining tax revenues, ignoring its effect in tax studies can lead to misleading results. To address this research gap, this study uses a three-part dynamic general equilibrium model to estimate the Laffer Curve and investigate the effects of tax deductions on the curve and taxable income.
Findings
The analysis focuses on the household, business, and government sectors, highlighting the significance of tax deductions within each.
Findings from this research show that, in the absence of tax deductions, the optimal tax rate for maximizing tax revenue in terms of labor income is below 45%, while for capital income, it is below 40%. In contrast, when tax deductions are present, tax rates exceeding 50% and 55% maximize tax revenue for labor and capital income, respectively. Furthermore, the elasticity of taxable income for both labor and capital remains relatively constant across scenarios, with a slightly higher value observed when deductions are considered. Regarding capital income, the elasticity consistently exceeds 1 due to the presence of varied capital deductions. In both cases, the elasticity exhibits a downward slope, gradually decreasing as the tax rate increases and approaching a value of 1. In contrast, the ETI associated with labor income remains below 37%, regardless of the presence or absence of deductions.
Furthermore, under tax revenue elasticity, the rate of reaction to the tax rate for the labor force is almost uniform in low tax rates and has a downward trend with the increase of the tax rate in all three cases (considering and not considering deductions). But in the case of reductions in the labor force, the amount of reaction is higher than the other two cases. While the elasticity of tax income from capital gains due to capital depreciation deductions is always greater than 1 and is downward in all three cases and gradually decreases with the increase of the tax rate and approaches 1.
Methodology
In the current research, to understand the effects of tax exemptions and deductions in the economic system, an attempt has been made to analyze the effects of tax deductions on the government tax revenues and the elasticity of taxable income and tax elasticity, in a simple three-part dynamic general equilibrium model including households, firms and government, three special cases regarding the absence of tax deductions and social security premiums should be investigated. To evaluate and estimate the model, first the calibrated parameters in previous studies were collected and then the results were obtained through MATLAB software.
Discussion and Conclusion
One of the important results of this research is the changes in the government tax income and the reaction of individuals in the form of taxable income, caused by the consideration and non-consideration of deductions and tax exemptions on the household and corporate sectors.
As it can be seen, tax revenues in the scenario of removing tax deductions are more than the other two scenarios, i.e. considering deductions, on the other hand, the elasticity of taxable income in the presence of tax deductions show a greater reaction than in the case of not considering tax deductions.
Iran has been experiencing consecutive budget deficits over different periods. As a result of reduced oil revenues much greater attention has been drawn to a more efficient and effective taxing system. So, a substitution in the government revenue system can potentially deminish the over-dependence of the Iranian economy on oil revenues, which can lead to far reduced deficits both in the long and short term.
In terms of deductions and exemptions as a factor affecting tax revenues, it can display a more realistic picture of an economy and take into account the existing economic realities. Therefore, the tax system should act in such a way that it moves in the direction of expanding the tax base. One of the solutions for this is realized through elimination of tax exemptions and deductions. It seems that such policies can prevent tax evasion, collecting more tax, and ultimately increase the motivation for work and activity and cause economic growth and prosperity
Making changes in the tax system is one of the basic and important needs for increasing government tax revenues. To achieve this, the tax system must move in a direction that increases the tax base. One of the most important solutions can be reducing tax exemptions and deductions. Since tax deduction plays an important role in determining tax revenues, ignoring its effect in tax studies can lead to misleading results. To address this research gap, this study uses a three-part dynamic general equilibrium model to estimate the Laffer Curve and investigate the effects of tax deductions on the curve and taxable income.
Findings
The analysis focuses on the household, business, and government sectors, highlighting the significance of tax deductions within each.
Findings from this research show that, in the absence of tax deductions, the optimal tax rate for maximizing tax revenue in terms of labor income is below 45%, while for capital income, it is below 40%. In contrast, when tax deductions are present, tax rates exceeding 50% and 55% maximize tax revenue for labor and capital income, respectively. Furthermore, the elasticity of taxable income for both labor and capital remains relatively constant across scenarios, with a slightly higher value observed when deductions are considered. Regarding capital income, the elasticity consistently exceeds 1 due to the presence of varied capital deductions. In both cases, the elasticity exhibits a downward slope, gradually decreasing as the tax rate increases and approaching a value of 1. In contrast, the ETI associated with labor income remains below 37%, regardless of the presence or absence of deductions.
Furthermore, under tax revenue elasticity, the rate of reaction to the tax rate for the labor force is almost uniform in low tax rates and has a downward trend with the increase of the tax rate in all three cases (considering and not considering deductions). But in the case of reductions in the labor force, the amount of reaction is higher than the other two cases. While the elasticity of tax income from capital gains due to capital depreciation deductions is always greater than 1 and is downward in all three cases and gradually decreases with the increase of the tax rate and approaches 1.
Methodology
In the current research, to understand the effects of tax exemptions and deductions in the economic system, an attempt has been made to analyze the effects of tax deductions on the government tax revenues and the elasticity of taxable income and tax elasticity, in a simple three-part dynamic general equilibrium model including households, firms and government, three special cases regarding the absence of tax deductions and social security premiums should be investigated. To evaluate and estimate the model, first the calibrated parameters in previous studies were collected and then the results were obtained through MATLAB software.
Discussion and Conclusion
One of the important results of this research is the changes in the government tax income and the reaction of individuals in the form of taxable income, caused by the consideration and non-consideration of deductions and tax exemptions on the household and corporate sectors.
As it can be seen, tax revenues in the scenario of removing tax deductions are more than the other two scenarios, i.e. considering deductions, on the other hand, the elasticity of taxable income in the presence of tax deductions show a greater reaction than in the case of not considering tax deductions.
Iran has been experiencing consecutive budget deficits over different periods. As a result of reduced oil revenues much greater attention has been drawn to a more efficient and effective taxing system. So, a substitution in the government revenue system can potentially deminish the over-dependence of the Iranian economy on oil revenues, which can lead to far reduced deficits both in the long and short term.
In terms of deductions and exemptions as a factor affecting tax revenues, it can display a more realistic picture of an economy and take into account the existing economic realities. Therefore, the tax system should act in such a way that it moves in the direction of expanding the tax base. One of the solutions for this is realized through elimination of tax exemptions and deductions. It seems that such policies can prevent tax evasion, collecting more tax, and ultimately increase the motivation for work and activity and cause economic growth and prosperity
Volume 27, Issue 3 (3-2025)
Abstract
Oil, as a primary source of energy, has a significant impact on promoting economic activities. Oil provides considerable part of the government's revenue sources. The price of oil has always fluctuated over the years due to various reasons including political, social, and economic developments in different countries. Since the price of oil affects different sectors of the economy, including agriculture, through the government budget and the revenue sources of the government, this study investigated the effect of OPEC oil price fluctuations on the value added of the agricultural sector from 1990 to 2019. The Generalized Autoregressive Score (GAS) Model estimated these fluctuations, while the Nonlinear Autoregressive Distributed Lag (NARDL) method estimated the long-term relationships. In addition to OPEC oil price fluctuations, variables such as the consumer price index, employment in the agricultural sector, and the trade openness degree were examined in the model. The results showed a negative effect of OPEC oil price fluctuations on the agricultural sector's value added. Furthermore, the trade openness had a positive effect on the agricultural value added in the long term. Results indicate that oil income is one of the most important issues that decline agricultural sector's value added, and the government should control this negative relation to develop agriculture as a vital part of the economy.
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