mohammad rezvani

The primary objective of this study is to investigate the impact of economic shocks—including the COVID-19 pandemic, changes in preferential exchange rate policies, and increases in energy carrier prices—on the marketing margin of chicken meat in Iran. Utilizing the theoretical framework of Piggott et al. (2000) and specifying a system of equations, the model was estimated using quarterly data for the period 2015–2022 via the Three-Stage Least Squares (3SLS) method. The findings revealed that the elasticity of substitution between farm inputs and marketing services is 0.34, indicating limited substitutability between these two inputs. Analysis of market power indices suggests the presence of market power within the processing and retail sectors. Shock analysis results demonstrated that both the COVID-19 pandemic and rising energy prices led to an expansion of the marketing margin (price ratio elasticities of 0.094 and 0.008, respectively). Conversely, the changes in preferential exchange rate policies resulted in a contraction of the marketing margin (elasticity of −0.032). Contrary to common perception, the results indicate that these shocks have a limited and negligible effect on the expansion of the marketing margin. This finding suggests that price increases are not primarily driven by an increase in the marketing margin; thus, any price intervention without a full understanding of market dynamics or evidence of profiteering behavior could lead to supply disruptions and diminish the incentives for economic actors. Consequently, priority should be given to rigorous and continuous monitoring of price movements and the identification of their underlying drivers to prevent the adoption of misguided policies affecting market performance.

Given the high concentration of the food industry market in Iran and the events of recent years, including the Covid-19 pandemic, it is essential to examine the potential for substitution between farm inputs and marketing services. This investigation will help determine the derived demand functions. Therefore, this research aimed at examining the possibility of substitution and the elasticity of substitution for farm inputs and marketing services regarding red meat, chicken, egg, and milk products from spring 2015 to winter 2022. The present research introduced two main innovations that would distinguish it from previous studies on the farm input and marketing relationship in Iran. First, to estimate price and income elasticities, the Quadratic Almost Ideal Demand System (QUAIDS) was employed. This model offers more reliable results than traditional methods due to its higher flexibility and precision. Second, this study explicitly incorporated the COVID-19 pandemic to investigate the effect of this shock on demand relationships and elasticities. The pandemic and its limitations directly impacted household food prices and consumption by creating uncertainty and disrupting supply chains. These measures sharply reduced economic activity, ultimately affecting household income and consumer behavior. By incorporating these changes into the model, this research provided a more accurate and up-to-date analysis of the farm input and marketing relationship, the results of which were vital for current market conditions.

To investigate the possibility of substitution between farm inputs and marketing services, Wohlgenant’s model (1989) was utilized. This analysis required the examination of price and income elasticities, which were obtained from the Quadratic Almost Ideal Demand System (QUAIDS). In order to calculate the price and income elasticities, the price and per capita consumption data of livestock products were needed. In this research, seasonal time series data for the period of spring 2015-winter 2022 were used. The information related to the price of livestock products was obtained from the Joint Stock Company of the Support of Livestock Affairs. To calculate per capita consumption, we first gathered data on the production amounts of red meat, chicken, milk, and eggs from the Joint Stock Company for Livestock Affairs. Then, by summing the amount of output and the amount of import of red meat, chicken, milk and eggs and deducting the amount of export from the concerned amount and dividing it by the population of the country, the amount of consumption per capita was calculated. The amount of export and import of red meat, chicken, milk and eggs was extracted from the export and import report of the Ministry of Agriculture-Jahad (MAJ) of Iran, which is published monthly. Also, according to the investigation of the possibility of replacing farm inputs and marketing services, the information related to the index of meat processing and storage and the production of dairy products were obtained from the data collected by the Central Bank of Iran (CBI) and the population information was obtained from the estimated data of the Statistical Center of Iran (SCI).

The results of the elasticity calculation indicated that red meat and milk were luxury goods for Iranian consumers, and chicken and eggs were essential goods; also, the demand for red meat, chicken, eggs, and fish was inelastic in terms of price. The characteristics of symmetry and constant returns to scale were checked using the Wald test and based on the chi-square statistic. The elasticity calculation results showed that, for Iranian consumers, red meat and milk were considered luxury goods, whereas chicken and eggs were categorized as essential goods. In addition, the demand for red meat, chicken, eggs, and fish was found to be inelastic with respect to price. Therefore, support policies should focus on providing the minimum protein requirements for low-income households through schemes such as electronic food coupons to prevent essential goods from becoming inaccessible luxuries. Furthermore, given the low values of both self-price and cross-price elasticities, utilizing pricing policies for goods substitution may not be very effective in applying optimal demand management and consumption pattern planning. It is important to note that as mentioned earlier, the Wald test was used to verify the characteristics of symmetry and constant returns to scale, based on the chi-square statistic. The results indicated that the characteristics of symmetry and constant returns to scale were upheld. In fact, the marketing sector for livestock products operates competitively with constant returns to scale. The positive elasticity of substitution found for red meat, chicken, eggs, and milk suggests a substitution relationship between farm inputs and marketing services. Additionally, the significant elasticity of substitution for chicken, eggs, and milk confirms the existence of substitution between these inputs.

Conclusion and Suggestions:

 Considering the potential for substitutability among farm inputs, the implementation of waste reduction methods is crucial. This includes utilizing more skilled labor in the slaughtering and processing of products, enhancing equipment and technology in poultry farms, supporting the growth of packaging industries, and improving transportation processes. These measures are suggested to extend the shelf life of products.

Urban agriculture, as a sustainable strategy for urban resource management and improved food security, requires effective environmental education programs. This study systematically reviewed and selected relevant studies to assess the impact of environmental education programs on various aspects of agriculture. Conducted with the aim of evaluating the effectiveness of environmental education in urban agriculture, this research is written from a meta-analytic perspective of scholarly articles. The primary objective is to identify and analyze trends, themes, and key findings reported in the literature regarding the effectiveness of environmental education in urban agriculture. To this end, a corpus of 70 English- and Persian-language articles on topics related to environmental education and urban agriculture, published in peer-reviewed journals between 1995 and 2024, was examined with scientific rigor and analytical scrutiny. The systematic review reveals that interactive and locally adapted educational approaches are more effective at changing behavior and sustaining outcomes than purely transmission-based models. Conversely, the absence of structured education can result in outcomes such as soil degradation, water pollution, and reduced ecological performance. The overall body of evidence emphasizes that the systematic integration of environmental education with participatory urban agriculture processes is not only a precondition for achieving sustainable development and urban ecological resilience, but also functions as a key strategy for managing environmental risks and securing socioecological benefits. This requires designing stakeholder-participatory educational programs, temporal continuity, ongoing evaluation, and adaptation to local urban conditions to ensure both optimal resource use and long-term environmental protection.

Given the double-digit inflation and various shocks—including economic sanctions and the COVID-19 pandemic—in Iran, the present study aims to investigate the causal relationship between inflation and inflation uncertainty during the period from April 2013 to September 2024 using econometric methods such as conditional variance modeling, the Autoregressive Distributed Lag (ARDL) cointegration test, and the Toda–Yamamoto causality test with Fourier approximation, which account for structural breaks. Accordingly, inflation uncertainty is first extracted from inflation data. After testing the stationarity of the inflation and inflation uncertainty variables, the cointegration relationship between them is examined. Subsequently, the causal relationship between inflation and inflation uncertainty is analyzed. The results indicate a unidirectional causal relationship from inflation to inflation uncertainty, consistent with the findings of Latan and Galag (2020) and Apergis et al. (2021). Therefore, considering that one of the critical challenges of Iran's economy is inflation—which exacerbates inflation uncertainty and influences economic decisions such as consumption, investment, and production—the importance of adopting economic stabilization policies aimed at reducing inflation is emphasized.

Revealing the land use changing is one of the effective tools for natural Resorces management and evaluating the ecosystem changes. The purpose of this study is revealing the effects of land cover changes on pastures using remote sensing data and GIS in the central sector of Harsin, Kermanshah.

In this study, the satellite images of Landsat 5 sensors TM 1985, Landsat 8 sensors ETM+ 2000 and Landsat 8 sensors OLI-TIRS 2015 have processed and analyzed. For this purpose, classification of these images has done with monitoring method by maximum likelihood algorithm, after atmospheric and geometric revisal. Then, images of each year classified into six classes of man-made, barren lands, garden, irrigated agriculture, dry farming and pasture. On the other hand, the NDVI index was used for better separation of pasture land and barren land; and slope layer was used for better separation of pasture land and dry farming.

Results showed that 83/92% of the area had no changes during 1982-2015, and also pastures use level has increased to 1941/36 hectare, man-made use level to 1095/47 hectare, garden use level to 89/07 hectare, and irrigated agriculture use level to 1233/00 hectare at the area.

based on the obtained results from this study, usage of RS and GIS techniques have the high functionality for providing land use maps and surveying the effects of land cover changes in pastures during time periods.

This study aimes to comprehensively understand the causal relationships between the agricultural sector, other economic sectors and GDP. Recognizing that neglecting structural breaks can lead to inaccurate results, we employ tests for variable stationary, co-integration, and causality, incorporating structural breaks using Fourier approximation. Our analysis uses seasonal data from spring 1991 to summer 2024. The results show a bidirectional causal relationship between the agricultural sector and both the industry and service sectors. Additionally, a unidirectional relationship exists from the agricultural sector to GDP. These results suggest that supporting increased value-added in the agricultural sector will, in turn, increase value-added in the industry and services sectors. Conversely, because the industry and service sectors can also increase the value-added of the agriculture sector, policies promoting growth in these sectors- , such as increasing the number of food processing facilities, expanding agricultural machinery manufacturing, and improving transportation infrastructure- will not only benefit industry and services but also drive growth in the agricultural sector. 

The mangrove forest ecosystem located in the south of Iran has been neglected in the past decades and has been seriously damaged and a part of these special forests has been lost. While with the relative advantage that this divine gift has brought to the people of the south of the country, from a scientific and economic point of view, we can try to improve the welfare of the people of the south and also preserve this valuable ecosystem. Therefore, the upcoming study aims to identify the damages caused to the mangrove forest ecosystem in Iran. For this purpose, the issues and problems resulting from human activities in the mangrove forest ecosystem were prioritized using the Analytical Hierarchy Process (AHP). The results show that the sub-criteria of industrial sector development in coastal mangrove areas, drought, inefficiency of organizational structure and lack of inter-sectoral cooperation, unplanned or unplanned tourism and lack of employment, existence of poverty and dependence of people's livelihood on mangrove forests as the most important problems of mangrove forests in the provinces were Sistan and Baluchistan, Bushehr and Hormozgan. Also, based on the obtained results, the criteria of managerial-structural factors, industrial factors, and socioeconomic factors respectively have the highest weight among the main criteria. The development of industry in coastal mangrove areas was chosen by experts as the most important threat to mangroves. Therefore, if the development of the industrial sector is done without considering the cost and benefits of the environment and natural resources, it will bring adverse effects. As a result, the feasibility of building industries is suggested in the best way.

In economic literature, any deviation of variable values from the long-term trend of their expected values is called shock. In a multi-level marketing model, where exogenous factors can change the market components (supply and demand), they can change the marketing margin. The currency jump at the end of 2016 and the increase in prices during 2017 led to the adoption of a policy of preferred currency allocation for the import of basic goods. The policy of allocating foreign currency with a preferred rate was implemented from August 2017 by designating 25 items as basic goods and with the aim of preventing the increase in the price of basic goods (price stability of basic goods). However, according to the report of the Research center of Iranian Islamic consultative assembly, the preferred exchange rate allocation policy has not been able to fully achieve the goal of price stability of basic goods. Finally, due to the problems in providing preferential currency and access to its benefits for the target communities, in May 2020, the preferred currency subsidy for imported inputs was removed. In this regard, due to the fact that a significant amount of subsidy was paid in the agricultural sector for livestock and poultry inputs, the removal of the preferred currency has strongly affected the activity cost of mutton. The destructive effects and economic impulses of the Covid-19 epidemic have been revealed in various sectors mutton, including the agricultural sector, and have had various consequences. The epidemic of Covid-19 generally affects the agricultural sector from two aspects of supply and demand. The lack of access to intermediate inputs and the decrease in labor supply due to the illness of the labor force and reduced physical ability, unwillingness to do work and the application of quarantine rules will lead to a decrease in production. The covid-19 pandemic has affected the agricultural sector not only in terms of supply but also in terms of demand. One of the most important effects of the Covid-19 pandemic is the decrease in economic growth worldwide. This problem has led to an increase in unemployment and a decrease in the purchasing power of people in the society. The present study, the behavior of the marketing margin of mutton has been investigated by considering the price risk and eliminating the preferential exchange rate and Covid-19 epidemic.

According to the method of Brester and Musick (1995), two patterns of farm-wholesale and wholesale (slaughterhouse)-retail marketing margin are estimated  simultaneously using the three-stage least squares approach. To estimate the model, monthly time series data for the period from April 2014 to January 2022 have been used.

The results show the positive effect of Covid-19 on the farm-wholesale marketing margin and the wholesale-retail marketing margin. The results also show that the response of the farm-wholesale marketing margin and the wholesale-retail marketing margin of sheep meat to the Covid-19 epidemic is very insignificant, and despite the impact of the Covid-19 epidemic on the supply and demand of products, the final price and foreign trade of products, the margin of sheep meat marketing has not changed much. Also, the results show that an increase in the price risk of the slaughterhouse causes a significant increase in the farm-wholesale marketing margin, and an increase in the retail price risk causes an increase in the wholesale-retail marketing margin.

Therefore, it can be concluded that mutton marketing agents show risk-averse behavior. Which means, if the price risk increases, the marketing margins will increase, too. The high concentration of the government on the processing sector, the inability of the private sector to compete with this sector and the high sensitivity of the price of slaughterhouse services to the market system of consumer inputs are among reasons which have that have caused problems in the structure of slaughterhouses in the country. It seems that breaking the monopoly in slaughterhouses and creating competition could be a solution solutions for price stability in slaughterhouses in the country.

Today, the importance of the mental health of the elderly and its tremendous impact on other aspects of their physical, social and spiritual health is undeniable, and it seems that treatments based on Quranic teachings play an important role in their mental and physical health. The purpose of this study was to investigate the effectiveness of meaning therapy based on Islamic teachings on the mental health and resilience of elderly men in Sanandaj. : The statistical population of this study included 110 elderly men aged 65 and above in the elderly care center of Sanandaj in 2024, of which 40 people (20 in the experimental group and 20 in the control group) were selected by convenient sampling method from two nursing home centers. The tools of data collection were Goldberg (1979) mental health questionnaires and Conner and Davidson (2003). Meaning therapy intervention based on Quranic teachings was implemented in 10 sessions of 90 minutes twice a week in the experimental group and the control group did not receive any training. Data analysis was done with descriptive tests (mean and standard deviation) and covariance analysis using SPSS-24 software. The results of multivariate covariance analysis showed. Meaning therapy based on Islamic teachings is effective on the mental health and resilience of the elderly in Sanandaj at a significance level of P<0.001 Considering the effectiveness of meaning therapy based on Islamic teachings on mental health and resilience, this therapy can be used to reduce the psychological problems of the elderly.

In many countries, agricultural product markets face the challenges related to pricing inefficiencies across various sectors and marketing channels. A major source of this inefficiency is asymmetric price transmission, where price increases and decreases at one level of the marketing chain are transmitted to other levels at different rates. The impact of price changes at one market level on others (i.e. how price transmission functions) significantly affects the welfare of producers, marketing agents, and consumers. Asymmetric transmission benefits intermediaries while harming producers and consumers by imposing additional costs. Examining vertical price transmission reveals power imbalances among supply chain actors, allowing researchers to identify bottlenecks, market power, and inefficiencies within the system. Furthermore, researchers can assess the impact of policies (like subsidies) on supply chain actors by analyzing how these policies affect price transmission. Understanding vertical price transmission is crucial for designing effective pricing policies and ensuring market stability. Analyzing how price shocks propagate through the chain improves decision-making, regulations, and stakeholder support, ultimately leading to improved food access, price stability, and enhanced food security. Therefore, considering the importance of price transmission, this study aimed at evaluating price transmission behavior at different levels of the chicken meat market from April 2014 to March 2024. Additionally, to assess the impact of the COVID-19 pandemic and the elimination of preferential currency, two dummy variables were added to the model. For the COVID-19 dummy variable, a value of one was assigned to the months from March 2020 to March 2022, and zero to all other months. Similarly, for the preferential currency elimination dummy variable, a value of one was assigned to the months from May 2022 to March 2024, and zero to all other months. To investigate the price transmission, the stationarity of the variables and the cointegration between them were first tested. Subsequently, the causal relationship between the variables was examined. Finally, the Error Correction Model (ECM) was applied to investigate the transmission process. To account for structural breaks resulting from different price shocks, Fourier approximation was used at all stages of the analysis. This study employed monthly time series data from April 2014 to March 2024 to examine price transmission across different levels of the chicken meat market. The results of the unit root test indicated that chicken prices at all three levels were first-order stationary. The findings from the Fourier cointegration test, which examined the cointegration relationships between chicken prices at different levels, indicated a number of causal relationships as follows:Between the price of live chicken at the poultry farm and the price of chicken meat at the slaughterhouse.Between the price of chicken meat at the slaughterhouse and the price of chicken meat at the retail level.Between the price of live chicken at the poultry farm and the price of chicken meat at the retail level.These results suggest a bidirectional causal relationship at various levels of the chicken meat market. In other words, the price of chicken at any level is influenced not only by the prices at other levels but also exerts an influence on them. Consequently, the effects of various shocks, whether positive or negative, are not limited to production but are transmitted to the prices at the slaughterhouse level and consumer prices. In addition, shocks in the market also affect the prices at the farm (poultry farms) level. The study findings indicated that the elasticities of price increases were greater than those of price decreases at different levels, and the symmetry test in the short run revealed the evidence of asymmetric price transmission. In contrast, the long-run symmetry test showed that the price transmission was symmetric across various market levels. The results also highlighted some positive effects of the COVID-19 and the elimination of preferential currency on chicken price changes at the retail level, suggesting that the COVID-19 pandemic and the elimination of preferential currency had increased the price volatility. However, considering the estimated elasticities, the response of chicken meat price changes at the retail level to the COVID-19 pandemic and the elimination of preferential currency was relatively negligible.Conclusion and Suggestions: Despite the asymmetric price transmission in the short run, it is evident that government intervention is necessary to correct the pricing process. Therefore, it is recommended to ensure the supply of poultry inputs at reasonable prices, support domestic production of poultry inputs, allocate bank facilities under favorable conditions for poultry farmers, and improve the supply chain to reduce production costs. Due to the asymmetry in price transmission in the chicken meat market, consumers often pay more than the total cost, resulting in losses, while marketing agents benefit from price fluctuations and uncertainty. To support the consumers, the government can implement policies such as stockpiling and distributing chicken during shortages or price increases and setting price ceilings for chicken during critical and necessary times.

One of the problems of a percentage of the elderly is loneliness, and these elderly people face high distress tolerance and reduced psychological health. This study was conducted to determine the effectiveness of compassion therapy on distress tolerance and social well-being of lonely elderly people.

The research method was a quasi-experimental design with a pre-test and post-test design. The statistical population included all lonely elderly people in Sanandaj city. Among these elderly people, 30 people were selected as available and randomly assigned to two experimental and control groups. The experimental group received compassion therapy intervention during 8 90-minute sessions. The research tools were the Simons and Gaher (2005) distress tolerance questionnaire and Keys (1998) social well-being questionnaire. The data were analyzed with descriptive statistics (mean and standard deviation) and analysis of covariance using SPSS-27 software.

The results showed that compassion therapy was effective on distress tolerance and social well-being of the elderly only in the post-test phase (P < 0.01). Based on the eta coefficient, the amount of this effect on distress tolerance of the elderly was only 46.8 percent and on social well- being was 52.8 percent.

Based on research findings, compassion therapy emphasizes body relaxation, a calm and compassionate mind, and mindfulness, which can play a significant role in calming the elderly and reducing their distress. Therefore, compassion therapy can only be used to increase distress tolerance and social well-being in the elderly. 

 Leaching of herbicides not only reduces their efficiency, but also increases soil and groundwater pollution. 2,4-D is a herbicide that can pollute soil and deep water. This experiment was conducted with the aim of investigating the effect of organic matter and soil texture on the permeability of 2,4-D herbicide through biological and canonical correlation analysis.

 In this experiment in 2018 in order to analyze and rely on organic matter and soil texture effects on the 2,4-D leaching, Bioassay and Canonical Correlation Analysis techniques were used. Experimental factors were soil organic matter (control, 2.5 and 5 weight percent of sheep short dung), soil texture (control, silty loam and loam soil) and herbicide dose (1.5 and 3 L ha-1). After supplying treatments, polyvinyl chloride pipes benefited for soil retention then herbicide inoculated with distilled water on the soil column. After three days all each 2-cm rings of column soil were exposed to bioassay test.

According to seedling wet weight of cucumber (test plant) in the most amount of dung fertilizer treatment, herbicide leaching front estimated till six cm depth. Whereas this horizon measured 10 cm for the control soil. In sandy soil too, wet weight loss was measured until 12 cm soil depth. In other words, with decreasing organic matter and increasing soil porosity, 2,4-D penetration raised as 6 cm depth.

 Dung fertilizer and heavy soil lead to herbicide immobility and 2,4-D application is not suitable in the young gardens with shallow roots.

Improvements in power electronic technology and devices cause DC microgrids (DC MGs) to be utilized in which the integration of DC distributed generation (DG) sources and loads into the power system is facilitated. Since the power sharing between DG sources and DC bus voltage regulation are two important control objectives in these microgrids, a two-layer hierarchical control strategy is implemented in this article to achieve these goals. The traditional drop control method is employed in the primary layer, but since it is not able to achieve these goals simultaneously, therefore, the proposed secondary control layer which is based on the proportional-integral cooperative distributed averaging (PICDA) secondary control strategy is introduced to overcome the challenges and achieve accurate voltage regulation. The proposed PICDA strategy has high flexibility due to the lack of prior knowledge of the grid topology and has a high convergence speed in reaching the control reference point. An islanded DC MG is simulated in MATLAB/Simulink software environment to verify the effectiveness of the proposed method, and the results of the proposed secondary control strategy are compared and analyzed with another distributed method under different operating scenarios, and the outperformance of the PICDA control method is confirmed.

Students’ lifestyle affects different aspects of their lives, including mental health. Islamic lifestyle and increase in mental health led to progress and growth of students. The aim of the present study was to investigate the relationship between Islamic lifestyle and normal lifestyle with psychological health of students in Kerman city. This descriptive research was correlation type. The statistical population of this research was all second-grade high school students in Kerman city, 480 of them were selected as a sample by multi-stage cluster random sampling method. In order to collect data, Kaviani’s Islamic lifestyle questionnaires (2008), Miller and Smith’s normal lifestyle (2002) and Goldberg and Hiller’s (1979) psychological health questionnaires were used. Data analysis was done by Pearson’s correlation coefficient and regression with SPSS version 24 software. The results of the findings showed that the Islamic lifestyle is more related to the psychological health of students than the normal lifestyle. According to the results of the research, it can be said that it is recommended to pay attention to the Islamic lifestyle in order to reduce the psychological problems of students.

Due to the position of meat products in the food pyramid and its importance in maintaining people's health and that economic sanctions can have a significant effect on meat consumption through the channel of increasing production costs and increasing the price of meat, the purpose of this research is to investigate the existence of failure There is a structure in the preferences of the meat consumption basket of urban households using the parametric approach and the switching regression framework developed by Ohtani and Katayama (1986) in the period of 2001-2013. The results show a structural failure (change) in preferences suddenly in 2017 and after the withdrawal of the United States from the JCPOA. The results show that after the withdrawal of the United States from the JCPOA, the price of chicken meat has decreased and the price of fish has increased, so that chicken meat has changed from an attractive product to an inelastic product. This result shows that consumers have become dependent on chicken meat and are willing to pay more to buy it. In such a situation, it is important to have adequate and optimal monitoring of the price of chicken meat, because people are forced to pay any price for chicken meat, and the changes of this product can cause the consumption basket of urban households to fluctuate greatly. Also, the estimation of income elasticity shows that chicken meat has changed from a necessary commodity to a luxury commodity after the sanctions. Therefore, to support consumers, it will be the right decision to use income tools and policies that lead to increasing the liquidity of urban households.

Examining the behavior of consumers of various types of consumer goods in relation to the changes of different price and non-price factors and the effect of each of these factors on demand is considered as one of the important economic issues. Estimating the demand function and calculating the elasticities of different groups of goods is one of the most important tools for investigating consumer behavior to know his preferences, and any policy and planning related to consumption requires analyzing the consumption pattern of households and knowing the position of each group of goods in the household budget. The large number of products and the lack of availability of sufficient information about consumer behavior make analyzing their behavior difficult. Aggregation goods and use of composite commodity are considered as an effective solution to deal with issues such as the unavailability of detailed information of each item, heavy costs of data collection, the presence of missing observations, the occurrence of collinearity problems, and the limitation of degrees of freedom by researchers. But it is important that the grouping is done correctly and consistently, because incorrect grouping appears as a specification error in the demand system and affects the extent of estimated parameters and elasticities as well as the test of the assumptions of demand functions, the result of which is presenting a false picture of consumer behavior and creating deviations in policies. Therefore, with respect to the importance of grouping and aggregation of different goods, this study aimed at investigating the conditions of aggregation of animal protein products including red meat, fish, chicken, milk and eggs using the methods of weak separability and generalized composite commodity for Iranian households in the period of 2004-2021. The hypothesis of the research in the method of weak separability was that in the group of animal protein products, the products of three groups of meat (red meat, fish and chicken), milk and eggs could be identified as three composite groups and then, the above three groups considered as one composite group with the name of the group of animal protein products; also, the hypothesis that red meat, fish, chicken, milk and egg products could be specified as a composite group was tested using the generalized composite commodity method. In the present study, the Quadratic Almost Ideal Demand System (QUAIDS) was used to investigate the weak separability. The results of the adjusted Wald statistic related to weak separability showed that the product group of animal protein products (red meat, fish, chicken, milk and eggs) could be separated into three groups: meat, milk and eggs. In fact, the result of the test did not reject the assumption that consumers first would allocate a part of their expenses to the group of edible goods regardless of its type; then, the act of allocation between different types of groups of edible goods would be done based on their prices. The study results indicated that the red meat and fish were found to be luxury goods while chicken, eggs and milk were known as essential goods for Iranian households. Own-price elasticities of all types of animal protein products were negative according to theoretical expectations based on the maximization of consumer utility. The highest absolute value of own-price elasticity was related to the red meat (-2.44), which shows that the consumption of red meat is very sensitive to price changes. The lowest absolute value of own-price elasticity was related to the eggs (-0.40). Following an increase in prices of commodities, their demand does not decrease significantly. The absolute value of the elasticity of the price of fish and chicken also shows the sensitivity of the consumption of fish and chicken to price changes, so if the goal is to increase consumption, the price reduction policy can be effective.  Due to the high cross elasticity coefficients of the demand for the red meat and chicken as well as the fish and red meat, it can be expected that following the change in the price of red meat, the demand for the chicken meat and the change in the price of the fish meat will significantly change the demand for the red meat. Therefore, in the application of optimal demand management and consumption pattern planning, the use of proxy product price policies can be effective.

The aim of this study was to investigate the role of social responsibility, organizational intelligence and self-esteem in predicting teachers' job self-efficacy.

The design of this research was practical in terms of its purpose, and in terms of its execution method, it was descriptive of the correlation type. The research community was made up of teachers from 22 districts of Tehran, and 300 of them were selected based on multi-stage cluster sampling. The participants responded to Riggs and Knight's (1994) occupational self-efficacy questionnaires, Carroll's organizational social responsibility (1991), Albrecht's organizational intelligence (2003), and Rosenberg's self-esteem (1965). The data were analyzed by Pearson correlation coefficients and multiple regression with simultaneous model in SPSS-27 software.

According to the findings, social responsibility, organizational intelligence and self-esteem had a positive and significant correlation with teachers' job self-efficacy (p<0.01). The results of multiple regression analysis also showed that the variable of social responsibility by 19%, organizational intelligence by 27% and self-esteem by 14% (60% in total) had the power to predict teachers' job self-efficacy (0.01). >p).

According to these results, in order to improve teachers' job self-efficacy, it is possible to provide a basis for improving their social responsibility, organizational intelligence, and self-esteem.

The misery index is known as one of the measures of economic well-being, and misery increasing index in a country means the deterioration of the economic and social welfare of the people of that country. Therefore, the worsening of the misery index, in adding to the economic effects, can bring many cultural and social consequences, so the identification and evaluation of macroeconomic factors affecting this index should be considered by planners and policy makers. Therefore, the main goal of this research is to investigate the factors affecting the misery index during the period of spring 2011 to summer 2023. In the present study, the framework of Shrestha and Bhatta (2018) and Fomby (1998), which helps a lot in choosing appropriate methods, has been used to analyze time series data. The results show that some variables are stationary and others are Cointegration of the first order, and based on the framework of Shrestha and Bhatta (2018), the Autoregressive Distributed-Lag Model should be estimated. The model estimation results show the positive effect of the uncertainty index on the misery index in the long term. Also, the effect of the exchange rate variables in the free market and the participation rate on the poverty index is positive, and the labor productivity variable has a negative effect on the poverty index. The results of this study can be used in such a way that in addition to the necessity of controlling exchange rate fluctuations, attention to the correct announcement of applied policies and the timely release of economic information that leads to the reduction of economic policy uncertainty can help to reduce the misery index.

Inflation as an undesirable economic phenomenon in recent years has had devastating effects on Iran economy. This made economic researchers devote plenty of reports and researches to the causes or ways to cope with inflation in Iran. In the present study, considering the importance of inflation, it was tried to take advantage of the econometric model to examine the effect of in Iran economy by using annual information from 1974 to 2021 and by using the Generalized Method of Moments (GMM). The results of the GMM model showed that the variables of labor wage index, liquidity volume, time-lag inflation and unofficial exchange rate growth have a positive and significant effect on inflation in Iran. Also, the GDP growth variable has a negative and significant effect on the dependent variable. The study suggests that in order to control inflation, the government in Iran should consider issues such as stability in economic policy-making, adopting appropriate fiscal policies, especially through budgetary discipline, and consistency of monetary and fiscal policies to curb inflation, to be important.

The global economy has witnessed rapid events over the past few years, which causesconcerns about climate change, and uncertainties. Over the past few decades, greenhouse gas emissions have been identified as one of the main causes of global warming, which eventually leads toclimate change. Therefore, investigating the effective factors on increase in carbon dioxide emissions as one of the most important types of greenhouse gases is of particular importance. In this regard, the purpose of this study is to investigate The effect of effective factors on carbon dioxide emissions in Iran, emphasizing the effect of economic policy uncertainty using Autoregressive distributed lag model (ARDL) during the period of 1997-2020. The research results indicate thatthat in the long term, the economic policy uncertainty variable has a positive effect on carbon dioxide emissions and reduces the quality of the environment. Also, regarding the other investigated variables, it can be stated that the consumption of renewable energy has a negative and significant effect on the emission of carbon dioxide and that they are compatible with the environment and help to improve the quality of the environment. Also, urbanization has a negative effect on carbon dioxide emissions. Considering thatOne of the reasons for the higher uncertainty index in low-income economies is the more unstable economy (they are more damaged by external shocks) and more domestic political shocks. therefore, it is suggested that long-term and stable policies be adopted by the government and help to improve the quality of the environment by paying attention to the correct announcement of applied policies and the timely publication of economic information that will lead to reducing the Economic Policy Uncertainty. Also, anticipating global uncertainties, adopt policies to reduce their effects.

In this research the effect of planting date and Bentazon application on control of weeds, and soybean yield was investigated.

Methods and Materials:

 Experiment conducted as split plot in a randomized complete block design with 4 replicates. Mainfactor included five planting dates (20 April, 4 May, 18 May, 2 June and 16 June) and subfactor was herbicide application including without and with bentazone application.

Delay in planting date and herbicide application, wild melon, and black nightshade control increased both at 10 and 30 days after spraying. The late planting date reduced soybean economic (29.2%) and biological yield (41.1%). Delay in planting date reduced the biomass of wild melon (99%) and black nightshade (61%) and other weeds (82%). Herbicide application decreased the biomass of wild melon (51%) and black nightshade (92%) and other weeds (71%). Soybean yield in early planting date was higher (71%) than late planting date. In the late planting date, density of wild melon and black nightshade was lower than early planting date. Delay in planting date accelerated flowering, and reduced ripening period, seed production, and yield.

The early planting date of soybean along with the application of bentazone reduces weed growth, crop damage and increases soybean yield that can be recommended to farmers.

  it is important to correctly estimate income and price elasticities and the impact of economic sanctions on the consumption behavior of Iranian households. So, the purpose of this paper is to investigate the consumption behavior of urban households in Iran by applying the quadratic almost ideal demand system (QUAIDS). Also, the existence of structural failure in the consumption basket preferences of tea, sugar, and sugar of urban households has been investigated using the parametric approach and the switching regression framework developed by Ohtani and Katayama (1986) from 1998 to 2022.The price elasticity of various types of tea, sugar, and sugar has increased after sanctions and Iranian and foreign tea, sugar and sugar have changed from non-elastic products to products with elasticity. The increase in price elasticities shows that with the increase in prices and inflation in the years after the sanctions, the sensitivity of consumers to price changes has increased. Therefore, considering the elasticity of the high price of products after the sanctions, it will be the right decision to use price tools to protect consumers.

In order to assess the competitive ability of soybean with P. alkekengi, a test was conducted at sari Agricultural Sciences and Natural Resources University. This research was carried out in two greenhouse and field condition. The treatments consisted of five planting ratios of soybean and P. alkekengi including: 25:75 (soybean - weed), 50:50 (soybean - weed), 75:25 (soybean - weed) and pure (100% soybean and weed species). According to the results the maximum yield of soybean in pot (39.60 g plant-1) and field conditions the maximum yield of soybean (141.44 g m-2) were obtained in weed-free conditions (soybean monoculture) and increasing soybean density reduce P. alkekengi biomass than the monoculture of this weeds. In pot and field conditions, the highest pod number per plant (171.66 and 201, respectively) and 100- seed weight (18.45 and 17.85 g, respectively) were observed in pure soybean (weed-free) cultivation. Also soybean tolerance to different densities of P. alkekengi showed that soybean can tolerate low density (25 percent) of P. alkekengi. Also study the competitiveness index (CI) showed that soybean at low density of physalis was higher and inhibit the weed biomass increment. The results showed that soybeans had a higher tolerance index and competitiveness index than the P. alkekengi. In general, increasing the density of P. alkekengi reduced the yield and yield components of soybeans in both potted and field conditions. In general, soybeans in low densities of P. alkekengi had a higher competitive ability than this species and inhibit the increase of weed biomass.

The effect of different heat-treatment temperatures on the magnetic, crystallization, and structural properties of 20SiO2.50FeO.30CaO (mol%) glass ceramics was studied. The initial glass was synthesized by the sol-gel method at 25℃  with a precursors to solvent ratio of 1/5. After aging the resulted gel for 24 h at room temperature, it was dried in an electric dryer at 110 ℃ . By heat treatment at different temperatures, different phases such as magnetite, maghemite, and hematite were crystallized in the glass. The maximum stability temperature of magnetite and maghemite were 360℃  and 440℃  respectively. By increasing the heat treatment temperature to higher than 440℃ , the oxidation of maghemite to hematite was occureds. The highest magnetization amount (1.9 emu/g) belonged to sample heat treated at 680℃ . By increasing the heat treatment temperature to 840℃ , the magnetization decreased to 0.8 emu/g, due to the oxidation of maghemite. By increasing the heat treatment temperature from 440℃  to 680℃ , crystalline size of maghemite was increased from 40 to 200 nm. By forther increment of temperature to 840℃ , the size of maghemite crystals decreased to 17nm, due to the oxidation of maghemite to hematite.AbstractThe effect of different heat-treatment temperatures on the magnetic, crystallization, and structural properties of 20SiO2.50FeO.30CaO (mol%) glass ceramics was studied. The initial glass was synthesized by the sol-gel method at 25℃  with a precursors to solvent ratio of 1/5. After aging the resulted gel for 24 h at room temperature, it was dried in an electric dryer at 110 ℃ . By heat treatment at different temperatures, different phases such as magnetite, maghemite, and hematite were crystallized in the glass. The maximum stability temperature of magnetite and maghemite were 360℃  and 440℃  respectively. By increasing the heat treatment temperature to higher than 440℃ , the oxidation of maghemite to hematite was occureds. The highest magnetization amount (1.9 emu/g) belonged to sample heat treated at 680℃ . By increasing the heat treatment temperature to 840℃ , the magnetization decreased to 0.8 emu/g, due to the oxidation of maghemite. By increasing the heat treatment temperature from 440℃  to 680℃ , crystalline size of maghemite was increased from 40 to 200 nm. By forther increment of temperature to 840℃ , the size of maghemite crystals decreased to 17nm, due to the oxidation of maghemite to hematite.

Hard tissues in the body consist of intricate three-dimensional composites, wherein approximately 30% constitutes collagen fibers, 60% mineral reinforcing particles, and 10% water. The mineral copounds of Natural bone tissues, such as calcium phosphate materials play a fundamental role in enhancing strength,hardness, and pressure resilience. The use of calcium phosphate bioceramics as bone grafts, such as Whitlockite(Ca18Mg2(HPO4)2(PO4)12), offers a promising method for treating bone defects due to its close chemical, biological, and crystalline resemblance to natural hard tissue. Also, Its biocompatibility, functionality, stability under acidic pH, negative surface charge, osteo inductivity and osteo conductivity, and maintaining Mg ions in their crystal structure make it an ideal bone substitute as compared to the other Ca-P bio ceramics.
This study aims to synthesize Whitlockite nanopowders using the chemical precipitation method with the precursers Mg(OH)2, Ca(OH)2, and H3PO4, and investigate the effects of pH, temperature, and Ca/Mg and Ca/P ions  ratios on the synthesized Whitlockite. Additionally, the impact of varying temperature and pH on the reactions during Whitlockite synthesis is explored. To characterize the synthesized powders, XRD, FTIR, SEM, and EDS analyses were employed. The results revealed that optimizing pH to 5 and temperature to 80°C yielded  Whitlockite with a crystal grain size of 61 nm. Increasing the ratio of (Mg2+ / Ca2+) ions concentrations in the reaction solution resulted in the formation of the Whitlockite phase and the magnesium phosphate phase (MgHPO4), while decreasing that ratio produced the monetite phase (CaHPO4) or dicalcium phosphate dihydrate (CaHPO4.2(H2O)). Furthermore, at 70°C, the formation of hydroxyapatite initially occurred, however the reaction favored the transformation into the more stable Whitlockite phase as pH values became acidic. In conclusion, this research highlights the significance of chemical precipitation for Whitlockite synthesis, providing valuable insights into the influence of pH, temperature, and ion ratios on the resulting crystalline phases. The findings contribute to a deeper understanding of the potential applications of Whitlockite as a bioceramic material for bone defects treatment.