f. seifi

Bitcoin as the current leader in cryptocurrencies is a new asset class receiving significant attention in the financial and investment community and presents an interesting time series prediction problem. In this paper, some forecasting models based on classical like ARIMA and machine learning approaches including Kriging, Artificial Neural Network (ANN), Bayesian method, Support Vector Machine (SVM) and Random Forest (RF) are proposed and analyzed for modelling and forecasting the Bitcoin price. While some of the proposed models are univariate, the other models are multivariate and as a result, the maximum, minimum and the opening daily price of Bitcoin are also used in these models. The proposed models are applied on the Bitcoin price from December 18, 2019 to March 1, 2020 and their performances are compared in terms of the performance measures of RMSE and MAPE by Diebold-Mariano statistical test. Based on RMSE and MAPE measures, the results show that SVM provides the best performance among all the models. In addition, ARIMA and Bayesian approaches outperform other univariate models where they provide smaller values for RMSE and MAPE.

Edris Bedlisi (861-926/ 1457-1520), son of Sheikh Hosam al-Din, was one of the emperors of his time who emigrated to Anatolia during the reign of King Ismail and came to the court of Sultan Bayazid II. He became the Sultan’s special scribe and courtier, and Sultan Bayazid commissioned him to compose Tarikh-e Al-e Osmān in Persian, in the style of Tārikh-e Jahangoshā, Tarikh-e Vassāf al-Hazrah, and Tārikh-e Mo’ini, but sultan, because of the misconceptions, did not deliver the promised reward to Edris Bedlisi. Then Edris went to Mecca and from there wrote a lamentable letter to the king. In the present article, the author intends to re-read and introduce Edris’ text after a brief description of Sultan Bayazid and Edris Bedlisi.

Inflammatory myofibroblastic tumor (IMT) is a rare tumor with unknown etiology which usually occurs in children and adolescents. It is composed of myofibroblastic spindle cells intermixed with inflammatory cells. Our case was a 15-year-old boy presented with fever, weight loss, anemia and epigastric mass. Radiographic studies showed periduodenal mass with duodenal compression and mild mucosal thickening. Sonography and duodenal biopsy were not contributory. In laparatomy, a peri-duodenal mass with duodenal adhesion was seen during the resection, perforation of duodenum and extrahepatic bile duct occurred. Consequently, duodenostomy and anastomosis of bile ducts were performed. On histological examination, IMT was diagnosed. Manifestation resolved after the removal of the mass and he remained free of recurrence within three years after discharge. Based on the fact that IMT is now generally considered to be a potential neoplasm, clinicians must consider it and it should be added to the list of differential diagnoses of anemia and abdominal mass. In addition, despite benign histological features, a risk of aggressive behaviors of the tumor,a long term clinical and radiological follow up of the patients is necessary.