پیشرفت های حسابداری (20089988)(1)pp. 64-97
در شرایط عدم اطمینان، درباره وضعیت آتی شرکتها و بازار سرمایه ابهام وجود دارد. در این شرایط ورود علائم اطلاعاتی مانند اعلام سود می تواند عدم اطمینان را کاهش داده و به تجدید نظر در باورهای پیشین سرمایه گذاران منجر شود. با این حال، علائم اطلاعاتی دقیق تر تاثیر قوی تری بر واکنش سرمایه گذاران دارد. هدف پژوهش حاضر بررسی واکنش سرمایه گذاران نسبت به اعلام سود شرکت ها با در نظر گرفتن شرایط عدم اطمینان بازار و عدم اطمینان اطلاعات شرکت ها می باشد. بدین منظور نمونه ای شامل 162 شرکت پذیرفته شده در بورس اوراق بهادار تهران در دوره زمانی 1384 تا 1394 انتخاب گردید.فرضیه ها با استفاده از داده های ترکیبی و روش رگرسیون بررسی و آزمون شدند. نتایج نشان می دهد زمانی که در شرایط وجود عدم اطمینان بالا در بازار، واکنش سرمایه گذاران به اعلام سود شرکت ها بیشتر است. ولی زمانی که عدم اطمینان بالایی در اطلاعات شرکت ها وجود دارد این واکنش کاهش می یابد. بررسی همزمان عدم اطمینان بازار و عدم اطمینان اطلاعات بر واکنش سرمایه گذاران به اعلام سود نیز نشان می دهد اگرچه زمانی که عدم اطمینان بالایی در اطلاعات شرکت ها وجود دارد، واکنش سرمایه گذاران به اعلام سود کاهش می یابد ولی برخلاف انتظار، ضریب سود غیرمنتظره در شرایط عدم اطمینان بالای بازار کمتر از ضریب مربوطه در شرایط عدم اطمینان پایین بازار است.
Water Policy (13667017)23(4)pp. 930-945
Population growth, along with climate change, has exacerbaed the water crisis in local communities. The simplest and quickest response of governments to such problems is direct intervention in local governance. Such solutions are usually proposed without regarding the indigenous knowledge of the local people. These also include top-down policies on water issues, which disrupt local institutional arrangements and eliminate the possibility of collective action by stakeholders in reaching an agreement. A case study of one of the water basins in Chaharmahal Bakhtiari in Iran (the Gorgak River in Sureshjan city) using an institutional analysis and development (IAD) framework shows that in the past, people acted collectively to solve the asymmetric distribution and drought problem. But government intervention, which initially sought to improve water conditions, has disrupted the region s institutional arrangements and power asymmetries between exploiters. Our study used the IAD framework to examine changes in institutional arrangements due to the introduction of technology and government intervention by the game theory. It clarifies that government intervention in local institutional arrangements, even if designed with the intention of improving conditions, may lead to greater inequality due to disregarding physical and social conditions and local knowledge. This inequality can eventually worsen the situation. © 2021 IWA Publishing. All rights reserved.
Iranian Economic Review (10266542)20(4)pp. 581-598
While economic deterrence models are fully based on maximizing economic utility; social psychology models explain human behavior by examining the underlying attitudes, norms and beliefs. Tax morale is defined as the intrinsic motivation to pay taxes. However, determinants of tax morale need to be investigated for a more comprehensive understanding of tax morale. In this paper we analyze the most important determinants of tax morale in Iran using data from World Values Surveys (WVS). Determinants of tax morale are categorized into four main groups: social capital, conditional cooperation, demographic factors and economic situation of the respondents. Estimating ordered probit model, we find that conditional cooperation and economic situation have the most important effects on tax morality. However, some of the social capital variables like importance of politics and religion and demographic factors like gender and marital status don’t have significant effect on tax morale in Iran. © 2016, University of Teheran. All right reserved.
Journal of Environmental Studies (23456922)40(1)pp. 247-254
Introduction: Air pollution is one of the critical challenges in metropolitans around the world. According to World Health Organization (WHO), three millions people die from air pollution annually. In some studies mortality costs by air pollution was estimated. Social cost of air pollution was estimated 28990 billions Rials in Tehran city. The mortality cost by air pollution was estimated about 4.31% of GDP in Singapore. Air pollution was increased the mortality rate by 868 in Manchester city annually in 1992-98, where the social cost was estimated about £572 million. Recently air pollution has become a serious crisis in Isfahan city in Iran In this study the mortality cost by air pollution as a social cost was estimated in this metropolitan in 2010-2011. Also mortality rate and long run effect of air pollution were estimated. Material and methods: Air pollution has short run and long run effect on the mortality. Air pollution accelerate patient' death and also can shorten life expectancy of other citizens. In most empirical studies only short run effect was investigated using dose response function. In this study, an ARMAX model was used to decompose short run and long run effect of air pollution on the mortality: (1+θ1L+θ2L 2)(log(MORT) - SMOOTH90 [log (MORT =α + (β, +β2L+β3L2)AQI + (β 4+β5L+β6L2)TEMP +(1+γ1L +γ2L2)e (1) Where, MORT is daily mortality rate, AQI is air quality index, TEMP is the average of daily temperature and e is an error term. Also seasonality effect of the mortality variable was smoothed with locally weighted least squares smoothing approach with a bandwidth of 90 days. Long run effect of AQI on the mortality rate was calculated as: LRE=(β1+β2+β3)/ (1+θ1+θ2) (2) Also, Long run elasticity of the mortality to air pollution was calculated as: LREL= [(β1+β2+β3)/1+θ 1 + θ2]AQI (3) Where, AQI is the average of daily air quality index in 2010-211. To estimate the social costs of air pollution for t=0, at first relative risk ratio was calculated: RRR = Exp((β 1) × AQI) (4) Total mortality was then divided by RRR. Difference of this figure with the total mortality yield the mortality in t=0 due to air pollution. For t= 1, the RRR was calculated as: RRR = Exp ((β2-β1×θ1) × AQI) (5) By multiplying mortality in t=0.1 by blood money gives the approximate social cost of air pollution. Results and discussion: Data on the daily mortality rate, daily mean temperature, and Air Quality Index (AQI) was taken from Isfahan University of Medical Sciences, Isfahan Metrological Organization and Isfahan Environmental Protection, respectively in 2010-2011. The data are described in Table 1. (Table Presented) For mortality variable the Phillips - Perron tests are able to reject the null hypothesis of unit root. The Phillips - Perron tests statistics was - 781.75 for the log(MORT) variable with a five percent critical value of-29.5. The econometric results are reported in Table 2. This model includes one lagged value of AQI and a twice lagged value of temperature. Air pollution had significant effect in the mortality rate (Table 3). (Table Presented) The social cost of air pollution: To estimate the annual social costs of air pollution, relative risk ratio (RRR) was calculated as Equ. 4 for t=0: RRR=Exp (0.00059*95.13)=1.09146 The total mortality (12015) was divided to this figure yield 11008 implying 1007 more deaths. Next to calculate the RRR for t=l, the lag coefficient was calculated: -0.00035+ (0.00059*0.67898)= 0.00005 The relative risk ratio was calculated: Exp(0.00005*13.95)= 1.0047 Dividing the total mortality (12015) by this figure yields 11958 impling 17 more deaths. Therefore, air pollution has caused 1024 deaths in 2010-11 (annually 512). Multiplying by blood money, the annual mortality cost was estimated 345 billion Rials. Conclusions: Air pollution has increased significantly in Isfahan city in recent years. In this study the short-run and log-run impacts of air pollution on the mortality rate was estimated in Isfahan city. For this purpose an ARMAX model was used to approximate the entire distributed lag impacts of changes in the level of air pollution on the mortality rate. Results showed that, annually, air pollution has increased the mortality rate about 8.5%. Accounting for this phenomenon the social cost has 346 billions for the residents of Isfahan. Also a 1% increase in air pollution increase 0.123% daily the mortality rate.
