چکیده [English] Objectives: This research evaluates the effects of overconfidence, disposition effect and investors’ attention on the abnormal volume and abnormal returns of stocks through Interruption in independent variables. Method: It uses the unbalanced panel data regression technique to study a sample of 325 listed firms in Tehran Stock Exchange at weekly intervals between 2011 and 2016. Resutls: The results show that disposition effect and investors’ attention cause abnormal volume. In addition, with regards to abnormal return, the effect of investors' attention on abnormal return is significant in the regression model. The important point in this study is the investigation of the effect of behavioral biases on abnormal volume while generating abnormal returns. The results indicate that only investors’ attention causes both abnormal volume and abnormal returns. Also, in the case of overconfidence, the relationship between this bias and abnormal volume and abnormal returns is not significant.

Earning Response Coefficient (ERC) indicates the ability of earnings to explain changes in stock returns. Stock returns synchronicity shows the extent to which market and industry returns can explain changes in stock returns. In this study, we investigated the effect of Earning Response Coefficient (ERC) on the relationship between stock returns synchronicity with the abnormal return and abnormal volume of stock trading The statistical population of this study consisted of all accepted companies in the securities exchange of Tehran and statistical sample consisted of one 118companies. The data of this study is related to a ten-years period from 1385 to 1394. The data is sorted by year and company and is estimated through using Multivariate Regression Analysis of models and hypotheses of the study were assessed. The results corroborated a negative relationship between the stock returns synchronicity and ERC with abnormal return. There was no significant relationship between stock returns synchronicity and ERC with abnormal volume of stock trading.

The aim of this study was to investigate the effect of volume shock on abnormal stock returns. In terms of research method, this research is in the category of descriptive-correlational research and in terms of research purpose, it is in the category of applied research. The statistical population in this study is all companies listed on the stock exchange that 120 companies were selected as a statistical sample and the information of these companies during the years 1393 to 1399 from the database of Tehran Stock Exchange and Soft ¬New Rahvard ideas were extracted. EVIEWS software and data panel template were used to analyze the data. The results of the data panel model showed that there is a positive and significant relationship between volume shock and abnormal stock returns. Because the probability value of this variable (0.0032) is less than the standard value of 0.05. Therefore, the research hypothesis of a significant relationship between non-volume shock and abnormal stock returns is accepted. A coefficient of 0.098 indicates that with an increase of one unit in the volume shock of transactions, the amount of abnormal stock returns increases to the rate of 0.098 units. The results also showed that there is a significant negative relationship between equity returns and abnormal share returns. According to the results, there is a positive and significant relationship between financial leverage and abnormal stock returns. The results also showed that there is no significant relationship between firm size and profit margin with abnormal stock returns because the probability value of these variables is higher than the standard value of 0.05.

Objective: According to the instructions of the Tehran Stock Exchange Organization, companies admitted to the stock exchange are required to publish their reports and financial statements and other important information that can affect the price of the company's securities or investors' decisions based on accounting standards. One of these reports is the monthly activity report, which companies admitted to the stock exchange and over-the-counter must publish in the Codal Website within 5 working days after the end of each month. And if approved by the organization, it can be extended up to 10 working days. The researches carried out in relation to the content of the published information are mainly based on annual and quarterly earnings and income reports. Because firm earnings and income are always disclosed simultaneously in such studies, an unanswered question is whether windfall earnings alone, which are mainly influenced by company sales, can affect stock prices, in other words, change in monthly sales of firms can contain important information or not. In this research, due to the fact that monthly sales and quarterly profits are disclosed on different dates, an attempt is made to investigate the effect of disclosed sales on stock returns. Considering that it is expected that the publication of the monthly activity report of the firms will contain information content about their activities and performance, therefore it is expected that the market will show a reasonable reaction to the publication of these reports. In the monthly activity report of firms, the income of sales of goods and services of the firm is reported. This report has been provided to investors through the codal. ir since 2017. The usefulness of this report for investors can be examined by evaluating its informational content. Method: It is an event research. In such researches, the time of information release is considered as the time of the determining event and the price changes around it as a criterion to evaluate the market reaction. To evaluate the information content of sources, two main criteria including price-based and volume-based tests are used. The price-based test makes it possible to evaluate the market reaction on a certain day or a certain period of time through the way the price changes. This criterion is based on the theory that the price correction will occur simultaneously with the increase in the accuracy of information or disclosure. The volume-based test reflects the reaction of the trading volume at the time of the announcement or a desired period compared to the period when the relevant information has not yet been disclosed. Price-based tests reflect changes in the expectations of the market as a whole, while changes in trading volume reflect the expectations of individual shareholders in the company. Research hypotheses have been formulated based on the presence of good news or bad news based on the market's reaction to them. If the monthly activity report contains messages about changes in the firm's performance, market participants react differently to these changes (good or bad). In the research hypotheses, the change in the firm's performance that will contain good or bad news is defined based on unexpected sales. In this study, to evaluate the information content of the monthly activity report of firms, price changes and trading volume around the announcement time have been considered. Based on data related to 234 firms during the years 2017 to the end of Shahrivar 2020 and event study methodology, the market response to these reports has been studied. Results: The findings show that the monthly activity report contains important information for the market. The market reacts appropriately to published reports containing good news or bad news. With the release of good news, stock prices increase, and following the bad news, stock prices decrease, which in any case, the trade volume around the publication of the monthly activity report of firms, a significant increase is observed. Conclusion: The results of this research showed that the publication of the monthly activity report contains important information content that market participants react to. The results show that the market reacts quickly to reports that contain good news (the actual performance is better than the firm's expected performance), and as a result, the stock price and trading volume increase on the day of publication and two days after that, as well as the market reaction. Also, the market's reaction to reports containing bad news is accompanied by a decrease in price and an increase in trading volume on the day of the event and three days after the event. Monthly activity report as one of the information has important messages related to the current performance of companies. Investors can adjust their short-term strategies based on their forecasts of current firm performance, prior to the announcement of quarterly earnings.

The primary purpose of accounting is to provide the information that is needed for sound economic decision making. Accounting information includes information contained in financial statements that the manner and extent of the quality of the content and its presentation, influences the decision of investors. Therefore, the purpose of this study is to investigate the effect of accounting information quality in cumulative abnormal return with emphasis on institutional ownership and trading volume on predictability of stock returns. The statistical population of this study is the companies listed on the Tehran Stock Exchange and to achieve the purpose of the research, by filtering, the data of 160 companies listed on the Tehran Stock Exchange and in the period 2012-2020 using multivariate linear regression are reviewed and analyzed. Also, to test the second hypothesis, panel smooth transfer method (PSTR) was used. Findings showed that there is a significant relationship between the quality of accounting information and cumulative abnormal return. Institutional shareholders, however, asymmetrically moderate the relationship between the quality of accounting information and the cumulative abnormal return. This means that institutional shareholders up to 41% ownership level have a positive effect on the relationship between accounting quality and cumulative abnormal return and institutional ownership levels of more than 41% have a negative and significant effect on the relationship between accounting quality and cumulative abnormal return. Also, trading volume modulates the relationship between the quality of accounting information and the cumulative abnormal return.

Objective Investor reactions to market news are often reflected in changes in trading volume or stock prices. Earnings announcements typically result in abnormal trading volumes, as they provide new information about a company’s financial performance. Market uncertainty is another key factor that can influence trading activity during the earnings announcement window. Under uncertain conditions, investors may question the sustainability of a firm’s cash flows and overall profitability, leading to more cautious or reactive trading behavior. This research aims to investigate the impact of high market uncertainty on abnormal trading volumes during the earnings announcement window, considering the moderating roles of market-level information and firm size.   Methods To address the research objectives, three hypotheses were formulated. These hypotheses were designed to explore the impact of high market uncertainty on abnormal trading volumes during the earnings announcement window, considering the moderating roles of market-level information and firm size. Panel data and regression analysis were employed using Eviews12 software for data analysis and hypothesis testing. The statistical sample comprised 127 companies listed on the Tehran Stock Exchange from 2013 to 2022.   Results The results of the first hypothesis test indicate that market uncertainty has a positive and significant effect on abnormal trading volumes during the earnings announcement window. Specifically, under conditions of high market uncertainty, earnings announcements lead to increased abnormal trading activity. However, the results of the second hypothesis test show that market uncertainty does not have a significant effect on abnormal trading volumes in either small or large firms during the earnings announcement period. Contrary to expectations, the third hypothesis test results show that, under high market uncertainty, the abnormal trading volumes during the earnings announcement window are not greater in companies with higher market-level information compared to those with lower market-level information.   Conclusion The findings indicate that under conditions of high market uncertainty, earnings announcements prompt investors to reassess future cash flow expectations, leading to increased abnormal trading volumes. Furthermore, firm size does not appear to moderate the impact of market uncertainty on abnormal trading activity. This may be because market uncertainty affects transaction volumes uniformly across firms. For example, during periods of elevated uncertainty, both small and large firms may experience similar levels of abnormal trading, driven more by overall market sentiment than by firm-specific factors. Also, this phenomenon may be attributed to behavioral biases or other limiting factors. In companies with low market-level information, high market uncertainty significantly increases abnormal transaction volumes. However, in companies with high market-level information, no significant effect is observed. This may be because companies with high market-level information have multiple information sources that reach the market before earnings announcements, rendering the announcements less impactful. Conversely, in companies with low market-level information, earnings announcements under high market uncertainty provide new information that updates expectations and alters trading volumes during the earnings announcement window.

Background: Heart failure (HF) is a global pandemic and a serious health issue in elderly population. It is among the leading causes of mortality, which imposes immense economic burden and premature deaths. In the present study we evaluate the value of E velocity of mitral inflow/E’ wave of mitral annular velocity/stroke volume (E/e'/SV) index in relation to in-hospital outcomes in patients with acute decompensation of systolic HF. Methods: In this descriptive-cross sectional study, 59 patient admitted with the diagnosis of decompensated HF were selected, and echocardiography was done before initiation of treatment. E/e′ /SV ratio calculated for them before initiation of treatment, and then this index compared with duration of admission, treatment type, in-hospital mortality, and other echocardiographic finding including tricuspid regurgitation gradient (TRG), right ventricle (RV) size, RV function, and left atrium (LA) size. Pro-brain natriuretic peptide (Pro-BNP) and cardiac troponin-I (cTN-I) levels were also recorded. Findings: There was a significant statistical relationship between E/e’ /SV index with LV and RV function, ejection fraction (EF), and functional class (FC) factor, as well as prior hospital admissions rate. Conclusion: According to the results of present study, E/e’ /SV index is not related to the severity of disease, but has a significant relationship with FC and the number of previous admissions.

Abnormal head posture (AHP) is an important clinical sign which may be due to non-ocular or ocular causes. Because of disperse data in the literature, this review of articles was performed. Data base search with the keywords "abnormal head posture" was performed from 1975 to 2004. The main etiologies of AHP, case reports with specific causes, therapeutic interventions, and any significant points regarding AHP were gathered. An AHP should alert the examiner to search for various conditions and its proper interpretation is an important step in diagnosis and therapy. Ocular causes should be ruled out in any case of AHP. AHP due to ocular causes can be observed in conditions related to extraocular motility or may occur to increase quality of visual acuity or visual field. Comitant and incomitant deviations, supranuclear palsies, A and V patterns, nystagmus, and central nervous system disorders are causes of ocular torticolis. Facial asymmetry can be a feature of a long-standing congenital or acquired AHP.

Background: Sudden sensorineural hearing loss (SSNHL) refers to the condition in which sudden hearing loss happens and mostly occurs when waking in the morning and is followed by progressive hearing loss within 12 hours or less. SSNHL due to rapid accordance is comorbid to psychological reaction in about 90% of patients.Although SSNHL is idiopathic, some studies show a relation between platelet volume and this disease. The aim of this study was to compare the platelet volume between patients with SSNHL patients and a control group.Methods: In a case control study, during 2012-2013, 55 patients with SSNHL and 55 healthy persons were selected and serum level of mean platelete volume (MPV), wight blood cell (WBC), red blood cell (RBC) and platelet was compared between the two groups.Findings: The mean of MPV in the case and control group was 8.93±0.96 and 9.55±0.99 and the difference between the two groups was statistically significant (P<0.001). Also, the level of WBC and RBC in case groups was higher than the control groups (P>0.050).Conclusion: According to the results of this study, the high level of platelet, MPV and hematocrit probably have an effect on SSNHL, which should be mediated. However, another study with a larger sample size is recommended.