An Analysis of the invariance and conservation laws of some classes of nonlinear ostrovsky equations and related systems

A large class of partial differential equations in the modelling of ocean waves are due to Ostrovsky. We determine the invariance properties (through the Lie point symmetry generators) and construct classes of conservation laws for some of the models. In the latter case, the method involves finding the 'multipliers' associated with the conservation laws with a stronger emphasis on the 'higher-order' ones. The relationship between the symmetries and conservation laws is investigated by considering the invariance properties of the multipliers

Is Foreign Direct Investment a Cause of Environmental Degradation in Pakistan? An ARDL Approach to Cointegration

This study has investigated the empirical relationship between FDI and environmental degradation in Pakistan and 43 years of data is used in the study started from 1972 to 2014. Empirical tests show that there exist mix-cointegrating series, so ARDL bounds testing is applied to check the short-long run cointegration among the variables. Results concluded that FDI causes CO2 emissions in long and short-run both. To check the direction of causality between variables, an ARDL Granger test is applied. It proved that FDI and CO2 emissions have bidirectional causality and causing each other from both ways

Functional evaluation of the urinary tract by duplex Doppler ultrasonography in patients with acute renal colic

Purpose: To determine the role of duplex Doppler ultrasonography (DDU) in Patients with acute unilateral renal obstruction. Subjects And Methods:A total of 161 Patients with suspected renal colic due to urolithiasis were evaluated by DDU followed by intravenous urography (IVU). The mean intra-arterial resistive index (RI) and the difference of mean resistive index between both kidneys (delta RI) were determined for each person. An RI value of ≥0.70 and a delta RI value of ≥0.06 were taken as the discriminatory threshold for obstruction. IVU results were considered the reference standard against which renal DDU findings were compared. Results: IVU showed both kidneys to be normal in 51 Patients and with unilateral ureteric obstruction in 110 Patients. The mean RI for obstructed kidneys was 0.67 (0.048), which was significantly higher (P-value Conclusion: Delta RI is more sensitive and specific than RI in acute renal obstruction. However, due to relatively low sensitivity for detection of partial obstruction, DDU cannot replace IVU as the standard imaging technique

Retained stones in the common bile duct: results of management

Seventeen patients underwent treatment for retained common bile duct stones. In 7 patients the stones were removed via a T-tube tract using steerable catheters while 5 patients underwent ERCP and sphincterotomy and 5 underwent surgical re-exploration. Considering morbidity, mortality, success rate and patients\u27 stay in the hospital, non-operative modalities should be the treatment of choice for retained common bile duct stones

The Impact of Corporate Governance Mechanisms (ownership structure and board structure) on Dividend Policy of Companies

Based on the Agency literature, on the one hand, cash dividends paid to shareholders reduce free cash flows and reduce the risk of investment in non-optimal investing projects, and on the other hand, increase constant control on managers by capital markets. Accordingly, interest payments as a policy maker-works to reduce conflict of interest. Hence, this study is about the survey of effect of mechanisms of Corporate Governance on the dividend policy of the companies accepted by the Tehran Stock Exchange. Four hypotheses represented to test this effect. The population of this study involves all listed companies of the Tehran Stock Exchange. Taking consideration the limitations of the sample of the present study, 71 companies selected as the sample of this study. The present study discusses mentioned companies from 2009 to 2013. The methodology of this study involves using the past information. Using statistical methods, regression analysis using combined data by fixed- effects. The obtained results of this study are indicative that is not a meaningful relation between the mechanisms of Corporate Governance and the rate of dividend. Keywords: Corporate governance, outside boards, institutional ownership, and agency theory

Producing High Strength Aluminum Alloy by Combination of Equal Channel Angular Pressing and Bake Hardening

A combination of severe plastic deformation by equal channel angular pressing (ECAP) and bake hardening (BH) was used to produce high strength ultrafine-grained AA6061 aluminum alloy. 2, 4 and 8 passes of ECAP were performed, and the bake hardenability of samples was tested by 6% pre-straining followed by baking at 200 °C for 20 min. The microstructures obtained for various passes of ECAP were characterized by XRD, EBSD, and TEM techniques. The microstructures were refined from an average grain size of 20 µm to 212 nm after 8 passes of ECAP. Maximum bake hardenability of 110 MPa, and final yield stress of 330 MPa were obtained in the specimens processed by 8 passes of ECAP

The Straw that Could Break the Camel's Back: An Economic Analysis of Subsidies in the Iranian Economy

Subsidies and welfare payments play a large role in the Iranian economy. The numbers that appear in the government budget under welfare or subsidy payments are only the tip of the iceberg. A considerable part of subsidies paid by the Iranian government are hidden and do not appear in the budget. The government provides to the populace a number of goods and services at prices below their cost or far below prices prevailing in international markets. All said, the Iranian economy is crisscrossed with a network of hidden and visible subsidies that threaten the long-term health of the economy that the President himself has referred to as sick. To be sure, extending a social safety net to individuals and families who are economically vulnerable is a laudable act, and ranks high among the tasks of a modern government. Nevertheless, such undertakings have many economic implications. For a policy to be viable in the long run, all costs, apparent or hidden, and all tradeoffs should be considered. The objective of this paper is to evaluate the economic ramifications of Iran’s system of subsidies and President Khatami’s welfare proposal