An Investigation into the Constructive Role of Task-based Conflict within the Agency Theory

This thesis focuses on the agency relationship by observing the conflict's role within the principal-agent dyad. It specifically sets the focal point on one specific type of conflict, i.e., task conflict, and concentrated on corporate governance and the mutual interactions of corporate components as the main field of study. The role of conflict has been discussed under the agency theory (Amason and Schweiger, 1994; Jensen and Meckling, 1976; Smith, 2010), asserting that any conflict between management and the owner inflicts unwanted costs upon the organization, and as a result, leads to unsatisfactory conditions (Mirrlees, 1976). Nevertheless, the psychological studies and the experiments conducted regarding organizational behavior indicate that disagreement tends to positively affect collective performance (Jehn, 1995; Rahim, 2002; Shankman, 1999). The current dissertation tried to bridge the theory and practice of studying the conflict-of-interest in the principal-agent relationship. Furthermore, it demonstrated that the effect of conflict resolution can vary depending on the type of controversy, task type, and even the firm's industrial background. The current dissertation adopted the mathematical model from Holmstrom (1979) for the theory and developed it by adding the conflict clarification task. Theoretical findings indicate that conflict clarification efforts positively influence the total outcome under the new assumptions. Also, it suggests that in a company with high innovation potential, the principal's share of the outcome is higher when there is observable conflict clarification activity. The relationship between the management board and the shareholders is investigated in the practical setting. By employing a dataset collected from over 134 S&P 500 in 14 years, it was examined whether shareholders' activism positively affects the performance indicators of the firm. The results suggest a positive and significant effect of executive compensation (i.e., 11%) and corporate governance (i.e., 8%) proposals. Also, one extra executive compensation proposal is associated with 13% higher revenue

Comparison of Various Compressible Vorticity Confinement Methods and Development Two New Confinement Parameters

In this paper, vorticity confinement parameters are successfully developed for compressible flows. The first new confinement parameter is proportional to spectral radii of the flux Jacobian matrix. Therefore, the confinement parameter implicitly contains the local conditions of the flow field. This new method is named as lambda vorticity confinement method. In order to gain confidence in the applicability of vorticity confinement, it would be ideal to completely eliminate constant coefficients from confinement parameters. Because these constant coefficients should be determined for every problem by trial and error and it takes a long time. In the next part of this paper, a suitable relation is introduced for the vorticity confinement parameter that doesn’t need any constant coefficient. This new method is named as adaptive vorticity confinement method. Then the capability of these new methods is compared with the other vorticity confinement methods for solving shock-vortex interaction and three dimensional moving vortex problems

Improvement of Compressible Vorticity Confinement Method by Combining It with Vortex Feature Detection Methods

In the present study, the performance of the vorticity confinement method has been improved by combining it with the vortex feature detection methods. In the conventional vorticity confinement method, the only parameter to apply or not to apply vorticity confinement is the non-zero value of vorticity. On the other hand, the presence of vorticity in some cases, like the boundary layer and the shear layer flows, does not imply the presence of vortices. Applying the vorticity confinement at these points can lead to errors, in addition to loss of solution time. In order to solve this problem, using the combination of vorticity confinement method and four methods of vortex feature detection (nondimensional Q, nondimensional λ_2, nondimensional modified ∆, and the S-Ω correlation) the vorticity confinement term is applied only in vortex regions. In order to investigate the effects of this combination, the compressible Euler equation has been investigated for the problem of two-dimensional stationary single vortex at Mach number 0.5. The results indicate significant positive effects in reducing the solving time, decreasing the sensitivity of the solution to the amount of confinement parameter and significant elimination of the oscillation

In vitro Susceptibility of Helicobacter pylori to Licorice Extract

Abstract Helicobacter pylori is the causative agent of gastritis and peptic ulcer disease. Eradication of H. pylori is hard to achieve and often require multiple antibiotics regimens. These regimens are quite expensive and have substantial side effects. Licorice is a traditional drug which is frequently used for gastric discomforts in Iran. The susceptibility of H. pylori to the extract of licorice has been investigated in the present study. One hundred and eighty clinical H. pylori strains were isolated in this study. For comparison and control, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were also included in this study. Agar dilution assay was used to test the susceptibility of the clinical isolates of H. pylori to the Glycyrrhiza extract at different concentration. The assay plates had 25, 50, 100, 150, 200, 300 and 400 mg/ml of licorice extract. Licorice extract inhibited the H. pylori strains with a MIC range of 50-400 mg/ml. The present results show that therapeutically administered concentrations of licorice extract could have growth-inhibiting effect on H. pylori in vitro. The above preliminary experiments indicated strongly that licorice extract has some anti-H. pylori property and H. pylori shows susceptibility to licorice extract in concentration ranges that are achievable in the stomach. The resistance of other bacterial species indicates the possibility of selective therapy without adverse effects on the normal bacterial flora

Effects of gas properties and geometrical parameters on performance of a vortex tube

AbstractIn this paper, energy separation effects in a vortex tube have been investigated using a CFD model. A numerical simulation has been undertaken, due to the complex structure of flow. The governing equations have been solved by the FLUENT™ code in a 2D compressible and turbulent model. Three turbulent models, namely, RSM, Standard k-epsilon and Spalart–Allmaras, have been used. The Spalart–Allmaras turbulent model, which is the first equation, was not so bad in predicting temperature results, although the Standard k-epsilon model better predicts the results in most regions. The effects of geometrical parameters have been investigated. The results have shown that the hot outlet size and its shape do not affect the energy distribution in the vortex tube, and a very small diameter will decrease the temperature separation. Different kinds of gas have been examined for the vortex tube, and it was concluded that using helium as a refrigerant produces the largest energy separation

Antimicrobial Activity of Rosmarinus Officinalis on Vancomycin -Resistant Staphylococcus Aureus Isolated from Imam Reza Hospital Patients of Mashhad

Introduction and Aims Rosemary (Rosmarinus officinalis) belongs to Lumiaceae family and contains different properties and compounds. With emergence of Vancomycin resistance Staphylococcus aureus, it has been confirmed as a global issue. The aim of this study is the survey of methanolic extract of rosemary leaves on Vancomycin -resistant Staphylococcus aureus isolated from patients of Imam Reza hospital of Mashhad. Materials and Methods 150 bacterial samples have collected from Imam Reza hospital of Mashhad at the beginning of 2013 November. One of them was being resistance to Vancomycin antibiotic by Disk Diffusion and MIC (Minimum Inhibitory Concentration). Extracting from Rosemary was performed by Maceration method. The MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal concentration) has evaluated by reference method of Microdilution Broth. Results The result of this study demonstrated that the MIC and MBC for Methanolic extract of Rosemary on Vancomycin -resistant Staphylococcus aureus were 0.156×103 and 0.312×103 mg/ml respectively. Conclusion Bacterial resisting to antibiotics implies necessity of using of new compounds with antibacterial property. The methanolic extract of rosemary can inhibit the growth of Vancomycin resistance Staphylococcus aureus. Therefore it can be used as clinical purposes. * Corresponding Author: Academic Center for Education, Culture and Research (ACECR) Khorasan Razavi, Center of Pathological and Medical Diagnostic Services of Neyshabur. E-mail: [email protected]

Pattern of Infection and Antibiotic Activity among Streptococcus agalactiae Isolates from Adults in Mashhad, Iran

Background: One of the main causes of sexually transmitted diseases is group B β- hemolytic streptococci (GBS) multiplying in the genital tracts. Penicillin is the most common drug for the treatment of infections caused by these bacteria, but in patients suffering from Penicillin allergy, Erythromycin and Clindamycin are used as alternative therapeutic drugs against GBS. Recently, resistance to these drugs has been reported more often. In this study, efforts have been made to determine the prevalence and antibiotic resistance of GBS. Methods: Modified Christie Atkins Munch-Petersen (CAMP) test was conducted on over 2400 samples of urine and discharge taken from vagina, urethra and prostate. The drug sensitivity was performed by double disk sensitivity tests to Bacitracin, Trimethoprim, and Sulfamethoxazole and then the resistant samples were investigated by E-test to determine the minimal inhibitory concentrations (MICs) value. Results: Twenty-three vaginal and 10 urethral discharge, 27urine and 6 prostatic secretion samples were GBS positive. The most symbiotic microorganisms with GBS were strains of Enterococci (90%), Staphylococcus saprophyticus (25%) and Candida albicans (6%). The disk diffusion method showed 18 cases with Penicillin resistance (MIC: 1.5 mg/ml). Conclusion: Taken together, GBS carriers’ rate in this study was found 20.65% (8.24% men and 12.4% women). Furthermore, findings showed high-level resistance to Erythromycin and Clindamycin

Assessment of common turbulence models under conditions of temporal acceleration in a pipe

In this paper, transient flow in a pipe at Reynolds numbers (based on bulk velocity and diameter) ranged from 7000 to 45200 is numerically simulated using four common turbulence models. The models considered are the Baldwin-Lomax algebraic model, the k-e model with wall correction of Lam and Bremhorst, the k-w model and the k-e-v2 model of Durbin. The results of these models are compared with those of the recent experiments reported in the literature. The predicted velocity and delay period using the models compared well with measured values for short and long ramp-up flow excursions. The delay period of the calculated turbulence kinetic energy close to the pipe centerline is around 4 sec which agrees with the experiments. The k-e-v2 model was found to provide the best results compared to the measured data in the region away from the wall. At the end of the excursion near the wall, however, the results of this model differs from those of the experiments