Thin accretion disks around rotating black holes in 4D4D Einstein-Gauss-Bonnet gravity

Recently, Kumar and Ghosh have derived Kerr-like rotating black hole solutions in the framework of four-dimensional Einstein-Gauss-Bonnet theory of gravity and investigated the black hole shadow. Using the steady-state Novikov-Thorne model, we study thin accretion disk processes for such rotating black holes including the energy flux, temperature distribution, emission spectrum, energy conversion efficiency as well as the radius of the innermost stable circular orbit. We also study the effects of the Gauss-Bonnet coupling parameter $\alpha$ on these quantities. The results are compared to slowly rotating relativistic Kerr black holes which show that for a positive Gauss-Bonnet coupling, thin accretion disks around rotating black holes in four-dimensional Einstein-Gauss-Bonnet gravity are hotter and more efficient than that for Kerr black holes with the same rotation parameter $a$, while for a negative coupling they are cooler and less efficient. Thus the accretion disk processes may be considered as tools for testing Einstein-Gauss-Bonnet gravity using astrophysical observations.Comment: 18 pages, 8 figures, to appear in EPJ

A study of the relationship between organizational learning and EFQM excellence model in University of Tehran

The purpose of this research was to study the relationship between organizational learning and EFQM excellence model. In this survey, 300 faculty members in University of Tehran 2012-2013 academic year answered to two standard questionnaire of organizational learning that was compiled based on Gomez, Cespedes-Lorente, and Valle-Cabrer (2005) and standard questionnaire of EFQM excellence model (2010). Obtained results by Pearson's correlation coefficient showed the significant relationship between organizational learning and EFQM excellence model. Obtained Results from multi-correlation coefficient and step by step regression showed that the best predictor of EFQM excellence model is transfer and integration of knowledge, system thinking and openness and experimentation

A study of the relationship between organizational learning and EFQM excellence model in University of Tehran

The purpose of this research was to study the relationship between organizational learning and EFQM excellence model. In this survey, 300 faculty members in University of Tehran 2012-2013 academic year answered to two standard questionnaire of organizational learning that was compiled based on Gomez, Cespedes-Lorente, and Valle-Cabrer (2005) and standard questionnaire of EFQM excellence model (2010). Obtained results by Pearson's correlation coefficient showed the significant relationship between organizational learning and EFQM excellence model. Obtained Results from multi-correlation coefficient and step by step regression showed that the best predictor of EFQM excellence model is transfer and integration of knowledge, system thinking and openness and experimentation

A study of the relationship between organizational learning and EFQM excellence model in University of Tehran

The purpose of this research was to study the relationship between organizational learning and EFQM excellence model. In this survey, 300 faculty members in University of Tehran 2012-2013 academic year answered to two standard questionnaire of organizational learning that was compiled based on Gomez, Cespedes-Lorente, and Valle-Cabrer (2005) and standard questionnaire of EFQM excellence model (2010). Obtained results by Pearson's correlation coefficient showed the significant relationship between organizational learning and EFQM excellence model. Obtained Results from multi-correlation coefficient and step by step regression showed that the best predictor of EFQM excellence model is transfer and integration of knowledge, system thinking and openness and experimentation

A Modified Hybrid Genetic Algorithm for Solving Nonlinear Optimal Control Problems

Here, a two-phase algorithm is proposed for solving bounded continuous-time nonlinear optimal control problems (NOCP). In each phase of the algorithm, a modified hybrid genetic algorithm (MHGA) is applied, which performs a local search on offsprings. In first phase, a random initial population of control input values in time nodes is constructed. Next, MHGA starts with this population. After phase 1, to achieve more accurate solutions, the number of time nodes is increased. The values of the associated new control inputs are estimated by Linear interpolation (LI) or Spline interpolation (SI), using the curves obtained from the phase 1. In addition, to maintain the diversity in the population, some additional individuals are added randomly. Next, in the second phase, MHGA restarts with the new population constructed by above procedure and tries to improve the obtained solutions at the end of phase 1. We implement our proposed algorithm on 20 well-known benchmark and real world problems; then the results are compared with some recently proposed algorithms. Moreover, two statistical approaches are considered for the comparison of the LI and SI methods and investigation of sensitivity analysis for the MHGA parameters

Brane worlds and dark matter

Two problems related to dark matter is considered in the context of a brane world model in which the confinement of gauge fields on the brane is achieved by invoking a confining potential. First, we show that the virial mass discrepancy can be addressed if the conserved geometrical term appearing in this model is considered as an energy momentum tensor of an unknown type of matter, the so-called X-matter whose equation of state is also obtained. Second, the galaxy rotation curves are explained by assuming an anisotropic energy momentum tensor for the X-matter.Comment: 13 pages, 1 figure, to appear in IJMP

Assessment of the Prevalence of Staphylococcus Areus in Nose of the Surgical Staff of Hajar and kashani's Hospital in 2015

زمینه و هدف: استافیلوکوک طلایی یکی از شایع ترین علل عفونت های بیمارستانی است. این مطالعه با هدف بررسی میزان فراوانی حاملین بینی استافیلوکوکوس اورئوس و ارتباط آن با آلودگی صورت گرفت. روش بررسی: در این مقاله تحقیقاتی کوتاه در مرحله ی اول، نمونه ها به صورت تصادفی از دست کارکنان بخش های مختلف بیمارستان کاشانی و هاجر شهرکرد اخذ شد و پس از کشت، نتایج توسط نرم افزار SPSS و آزمون های آماری کای اسکویر و دقیق فیشر مورد تجزیه و تحلیل قرار گرفت. یافته ها: از 90 نفری که در مرحله ی اول انتخاب شدند، 44 نفر (8/48) در هر دو نوبت، نمونه ی دست آلوده داشتند. ارتباط معنی داری از نظر آماری بین تعداد حاملین بینی و آلودگی دست ها مشاهده شد (0/05>P). نتیجه گیری: این مطالعه نشان داد که حاملین بینی استافیلوکوک طلایی می توانند باعث آلودگی دست ها به این باکتری شده و این امر به انتشار این باکتری به خصوص در محیط بیمارستانی کمک می نماید