One of the most important factors that investors pay attention to in stock markets is stock price fluctuations, which is the basis for evaluating the performance of company managers. The performance of the company's stock includes the yield from the resources under the company's control and is considered a suitable criterion for reaching the set goals. In the meantime, one of the things that influenced widely on the world financial markets is the outbreak of the 2019 Covid-19 epidemic. The Covid-19 pandemic is known as a BLACK SWAN event since it was a rare, unexpected, unknown phenomenon with a high and universal impact. Therefore, the current research purpose is to investigate the fluctuations in the stock prices of petrochemical industry companies affected by the Covid-19 pandemic. For this purpose, 19 petrochemical companies of Tehran stock exchange were studied between 2017 to 2022. The data gathered daily and included 19 petrochemical companies in 220 working days for 5 years. The results showed that the shock caused by the growth of the corona virus initially caused a decrease in price volatility in petrochemical companies, but after two periods, the reaction of price volatility to the shock was positive. Finally, the shock effect disappeared after seven cycles.

In this paper two different methods are presented to approximate the solution of the fractional BLACK-Scholes equation for valuation of barrier option. Also, the two schemes need less computational work in comparison with the traditional methods. In this work, we propose a new generalization of the two-dimensional differential transform method and decomposition method that will extend the application of this methods for pricing barrier options of fractional version of the BLACK-Scholes model. Undoubtedly this model is the most well known model for pricing financial derivatives. This methods finds the analytical solution without any discretization or additive assumption. the approximate analytic solution is calculated in the form of convergent series with easily computable components, to solve the fractional BLACK-Scholes ‎equation.

Introduction:Forecasting sea conditions and its vital role in shipping, fisheries and professional affairs, is too obvious. Different models, accuracy and precision in this regard can effectively lead to a better understanding. One of the useful models is SWAN. For evaluating the performance of this model in aspect of executive and scientific both, study on verification of its products is required. In this study, the model outputs of wave height and period in the case of Bushehr and Assaluyeh have been verified. With this study it is tried on the accuracy of the model outputs with the corresponding values of Buoy and its performance on predictions 12, 24, 48, 72 and 96 hours studied and assessed.

Background: Fingers’,SWAN neck deformity is an uncommon sign in neonates. This deformity has much pathology in adults such as prolonged rheumatoid diseases, tearing or weakness of ligaments or increased spasticity of muscles. In this article we report on a neonate case of SWAN neck deformity and discuss the possible disorders which have possibly caused this deformity. Our infant is a known case of asphyxia so we are also going to discuss that SWAN necks may be a complication or a comorbidity of asphyxia. Case report: Our infant is a two month-old male preterm newborn, hospitalized due to seizures. The infant has a history of intrauterine growth retardation and perinatal asphyxia. On physical examination the patient was hypotonic and reflexes were decreased and there was a deformity on the hands which is very similar to SWAN neck deformity seen in adults. We requested different paraclinical modalities such as electroencephalogram, electromyography and nerve conduction velocity, computed tomography to rule out different possible diagnoses for the deformity (e. g., Ehlers Danlos syndrome, leukocyte adhesion deficiency). According to the results of the investigations, no reason was found for this deformity in the infant, and it seems that this deformity is one of the complications of asphyxia or has occurred in association with it. Conclusion: SWAN neck deformity is a very rare finding on neonates. It was observed in a newborn with perinatal asphyxia, and different commonly known causes of this deformity were ruled out in this newborn. Therefore, in our opinion, this deformity can possibly be one of the late manifestations of asphyxia in a newborn.

Wind-induced wave characteristics are one of the most important factors in the design of coastal and marine structures. Therefore, accurate estimation of wave parameters is of considerable importance. The wave climate study can be conducted by field measurements, empirical studies, physical modeling and numerical simulations. In this paper, the skill of a third-generation spectral model called SWAN has been evaluated in the prediction of wave parameters. The varying wind and wave climate of Lake Erie in the year 2002 has been used for evaluation of the model. The significant wave height (Hs) and the peak spectral wave period (Tp) were the parameters employed in the study and the model has been executed in a nonstationary mode. The linear and exponential growth from wind input, four-wave nonlinear interaction, white capping and bottom friction have been considered in the simulation. The results of this study show that in the investigated case, the average scatter index of SWAN is about 19 percent for significant wave height and 23 percent for the peak period. The error of the SWAN model in prediction of the wave height and period reduced about 3 percent after elimination of wave heights less than 0.5 meters.It was also found that using the cumulative steepness method for white capping dissipation yields worse results for significant wave height and better results for peak spectral period estimation. After using this method, the average scatter index for the prediction of Hs increased about 5 percent and decreased more than 4 percent for Tp. It should be mentioned that the computational time required by using this method is approximately more than twice that of the Komen option.