جواد غیاثی

"Economic development depends on institutional change and reform". A relative consensus on this statement has been created among economists. The main question of this research is "Where is the starting point of institutional change? What are the main actors and mechanisms of institutional change?" Many development thinkers have stopped after reaching this question, and only a handful of theories can be found regarding the formulation of institutional change. Emphasis on exogenous variables as a driver of institutional change is faced with the challenge of inaction and waiting for exogenous variables to change based on chance. On the other hand, endogenous institutional change also faces the theoretical paradox of free riding; Where, according to collective action theory, there is no reason for Citizens to participate in the process of institutional change. Therefore, both approaches, at least at the theoretical level, face challenges or contradictions.In this article, an attempt has been made by examining and systematic reviewing of six important theories of institutional change (Hayek's evolutionary approach, North's cognitive approach, Krasner's junctures theory, institutions as equilibrium approach, Acemoglu’s political economy approach, and Roderick's self-discovery approach), To analyze them and to evaluate how they face the above paradox. The results show that the analysis of theories based on the two elements of "factor of change" and "mechanism of change" provides a good opportunity to compare theories and finally it was concluded that in terms of the fuzzy variable of the degree of endogeneity of institutional changes, it can solve the theoretical and practical obstacles in the formulation of institutional changes.

Due to the undesirable phenomenon of graduate unemployment and its negative effects, Addressing the issue of how to major choice is of particular importance. The main question of the research is whether the existing signals of choosing a field have been effective in guiding people in accordance with the needs of the labor market? The method of this research is descriptive-analytical; It has been a combination of documentary studies, qualitative statistical analysis (descriptive statistics) and analytical statistics (cross-sectional econometrics). The findings of this study, which was conducted using the data of the years (2006-2018) and controlled by the province and the type of university, show in major choice of volunteers, no attention is paid to the unemployment rate of that field. The non-significance of the unemployment rate coefficient in the above model confirms the hypothesis that the unemployment rate of the field (main independent variable) does not explain the registration rate in that field (dependent variable), Therefore, the unemployment rate of the field in any of the six fields, in any type of universities and in any of the provinces, has no significant effect on the rate of major choice. According to the theoretical and experimental background of research in many other countries, there is a problem and weakness and they have followed solutions for it.

Investigating the causality between the futures and spot markets of a commodity is always an important question for market traders and policy makers. By launching financial derivatives including futures and options for saffron in Iranian commodity exchange since 1397, this question has also been raised in the Iranian saffron market. The main purpose of this paper is to determine the causality between the spot and futures markets of saffron. The required data were obtained daily from the Iranian commodity exchange as well as the Saffron World database during June 2018 to November 2019 and analyze based on Granger causality test and generalized autoregressive conditional heteroskedasticity (GARCH) models. The results show that, in general, there are no explicit causal direction, but by distinguishing between ascending and descending periods, it is clear that in the descending periods, absolutely, causality has been from futures market to spot market and in ascending periods, For some, causality has been from spot market to the futures.

Choosing an education field is individually one of the most important decisions of life; and from the perspective of the educational system and the labor market is an important social-economic process. Due to the effects of this decision, research in domain of modeling, identifying the factors affecting the choice of field and determining the weight of various factors, determining the optimality of choices from the perspective of labor market needs and finally designing and evaluating methods to eliminate mismatch between the field of study and job is very important. But this field of research in Iran is very neglected and lags behind in terms of analytical framework and method. For this reason, the question that what modeling frameworks, research methods, and policies are in place to address the field-job mismatch was selected as the central issue of the research and based on this, previous studies were categorized and analyzed. In general, three macro approaches were identified in modeling the behavior of the field selection; Modeling approach, investing in human capital approach and the mismatch approach. An examination of empirical research based on all three approaches shows that there is always a serious divergence between the outcome of discipline choice behavior and labor market needs. According to the results of meta-analysis, this gap has existed seriously over time and between different countries, even developed countries. Therefore, based on global experiences, various political interventions have been categorized and suggested to solve this problem.

Intrusive luxation is apical displacement of tooth into the alveolar bone due to bicycle accidents, sports accidents, falls, and fights. Intruded tooth is driven into the socket, compressing the periodontal ligament. Intrusion is considered as one of the most severe luxation injuries to affect permanent dentition. Intrusion injuries are often associated with severe damage to the tooth, periodontium, and pulpal tissue. The rare occurrence of this injury in the permanent dentition has resulted in limited studies to support suggested treatment regimens. Clinical treatment for intrusion is especially important because of the severe complications accompanying trauma.

This article reports traumatically intrusion of permanent maxillary central incisor which was followed by definite guidelines existed in management of traumatically Intruded permanent teeth. Also article is an overview of all available articles which are relevant with intrusion and provides all treatment modalities which are considered beneficial up today.

Instant care and root canal treatment for intruded tooth can play a major role in correcting the tooth position and subsequently improving function and appearance. Therefore, clinician's knowledge and skills has a crucial role in managing intrusive luxation.

Competetiveness measurement of markets is an important issue in economic analysis due to welfare and policy purposes. Specially,in agriculture products, there is important problems that vertical Price Transmission test can solve. " do producer/consumer price changes transmit to consumer/producer market? do price changes control with marketing agent for more profits?" In this servey using monthly data from march 2000 to april 2014, Asymmetry Price Transmission in iran's saffron market is evaluate. johansen cointegration test and granger causality is employed to longrun relation behavior and error correction model to price transmission behavior analysis. Results show bilateral longrun relation between consumer price index and producer price. also results show a symmetric price transmission in short and longrun periods. Finally due to symmetric price transmission, suggested to develope saffron bargains in goods bourse to beter market performance, specially for price transparency in interprovince and international retail markets.