Tahmin teknikleri ve dünya ham petrol fiyatlarının analizi

Son yıllarda, karar alma ve planlama süreçlerinin önemi iş ve bilim dünyasında sıklıkla vurgulanmakta ve gelecekte oluşacak koşulları tahmin etme yeteneği, sözkonusu süreçlerin kilit aşamalarından biri olarak görülmektedir. Tahmin tekniklerinin, planlama fonksiyonunun ayrılmaz parçası olarak kabul edildiği alanlardan biri de kuşkusuz enerji sektörüdür. Bu çalışma ile, önemli enerji ürünlerinden biri olan Dünya ham petrol fiyatlarının tahminine yönelik, fiyatlar serisinin kendi özelliklerine odaklı bir bakış açısı ortaya koyulmasına ve gelecekte yapılacak çalışmalara altyapı oluşturabilmesine çalışılmıştır. Dünya ham petrol fiyatlarının yıllık değerleri ile yıllık üretim miktarları arasında güçlü bir ilişki olmadığı görülmüştür. Üretim miktarlarının, fiyatların açıklayıcısı olarak kullanılmasının yeterli olmadığı durumlarda zaman serisi modellerinin kullanılması faydalı olmaktadır. Zaman serisi modellerinden, basit hareketli ortalama ve yanıt oranı uyarlamalı üstel düzeltme modellerinin performanslarının ön plana çıktığı görülmektedir.In recent years, the importance of decision-making and planning periods has been frequently stressed in business and scientific environments. The capability to predict future conditions has been identified as one of the key stages of these periods. One of the areas where prediction techniques are considered a vital part of planning is without doubt the energy sector. This work attempts to set forth a perspective on predictions for world prices of raw petroleum, one of the most important sources of energy. This focus here is on the particular characteristics of the price sequence and the aim has been to form a foundation for future work in this context. It has been observed that there is no strong connection between the yearly values of world raw petroleum prices and yearly production levels. In cases where production levels are not sufficient enough to explain price levels, it is useful to use the time-series models. In time series models, it has been seen that performance of simple moving averages and adaptive response rate models have come to the fore

Tahmin teknikleri ve dünya ham petrol fiyatlarının analizi

Son yıllarda, karar alma ve planlama süreçlerinin önemi iş ve bilim dünyasında sıklıkla vurgulanmakta ve gelecekte oluşacak koşulları tahmin etme yeteneği, sözkonusu süreçlerin kilit aşamalarından biri olarak görülmektedir. Tahmin tekniklerinin, planlama fonksiyonunun ayrılmaz parçası olarak kabul edildiği alanlardan biri de kuşkusuz enerji sektörüdür. Bu çalışma ile, önemli enerji ürünlerinden biri olan Dünya ham petrol fiyatlarının tahminine yönelik, fiyatlar serisinin kendi özelliklerine odaklı bir bakış açısı ortaya koyulmasına ve gelecekte yapılacak çalışmalara altyapı oluşturabilmesine çalışılmıştır. Dünya ham petrol fiyatlarının yıllık değerleri ile yıllık üretim miktarları arasında güçlü bir ilişki olmadığı görülmüştür. Üretim miktarlarının, fiyatların açıklayıcısı olarak kullanılmasının yeterli olmadığı durumlarda zaman serisi modellerinin kullanılması faydalı olmaktadır. Zaman serisi modellerinden, basit hareketli ortalama ve yanıt oranı uyarlamalı üstel düzeltme modellerinin performanslarının ön plana çıktığı görülmektedir. In recent years, the importance of decision-making and planning periods has been frequently stressed in business and scientific environments. The capability to predict future conditions has been identified as one of the key stages of these periods. One of the areas where prediction techniques are considered a vital part of planning is without doubt the energy sector. This work attempts to set forth a perspective on predictions for world prices of raw petroleum, one of the most important sources of energy. This focus here is on the particular characteristics of the price sequence and the aim has been to form a foundation for future work in this context. It has been observed that there is no strong connection between the yearly values of world raw petroleum prices and yearly production levels. In cases where production levels are not sufficient enough to explain price levels, it is useful to use the time-series models. In time series models, it has been seen that performance of simple moving averages and adaptive response rate models have come to the fore

Nadir bir mekanik barsak tıkanıklığı nedeni: İntestinal miyeloid sarkom

Myeloid sarcoma is a rare aggressive tumour that originates from immature extramedullary myeloid cells. It can be seen as a relapse in patients with acute myeloid leukaemia. Sometimes it can be seen in the form of a solid tumour without any evidence of leukaemia. A case of a 44-year-old male patient who was admitted with symptoms and signs of mechanical intestinal bowel obstruction was operated on. The operation findings showed small bowel obstruction due to a mass. The mass was then resected with end-to-end intestinal anastomosis. The resected mass pathology results were consistent with myeloid sarcoma. The post-operative period was uneventful and adjuvant therapy was applied. In this case report we aimed to evaluate the clinical signs and treatment modalities of small intestinal myeloid sarcoma.Miyeloid sarkom ekstramedüller immatür miyeloid hücrelerden kaynaklanan, nadir görülen agresif seyirli bir tümördür. Akut miyeloid lösemili hastaların relapsı olarak karşımıza çıkabilir. Bazen lösemi tanısı olmaksızın solid bir tümör olarak da görülebilmektedir. Mekanik barsak tıkanıklığı semptomları ile başvuran 44 yaşında erkek hasta opere edildi. Operasyonda ince barsak tıkanıklığına neden olan bir tümör saptandı. Tümör rezeke edilerek uç uca anastomoz uygulandı. Patoloji sonucu miyeloid sarkom olarak rapor edildi. Postoperatif dönem sorunsuz seyretti ve hastaya adjuvan tedavi uygulandı. Bu olgu sunumunda ince barsak miyeloid sarkomunun klinik bulguları ve tedavisinin irdelenmesi amaçland

Optimization of change in epicardial fat thickness for obese patients who lost weight via the bariatric surgery method using central composite and Box-Behnken experimental designs

Background. The aim of this study was to detect the optimal values for Age, Body Mass Index (BMI) and HOMA-IR of obese patients prior to surgery that results in a maximal decrease of visceral fat mass 6 months after bariatric surgery. Method. In this study, 33 experimental set-ups were designed. This study was approved by Baskent University Medical and Health Sciences Research Board (Approval number: KA16/281). The study data consisted of 40 obese patients who lost weight through the bariatric surgery between February 2015 and December 2016. The values of BMI, Age and HOMA for the obese patients who lost weight through the bariatric surgery were evaluated in three categories and at three levels; the response variable was determined as the Change in Epicardial Fat Thickness (1EFT). Results. As a result of CCD analysis, the optimum 1EFT = 2.571 was determined when Age = 30.52, BMI = 45.30, and HOMA = 34.62. As a result of the BBD analysis, the optimum 1EFT = 3.756 was determined, when Age = 38.36, BMI = 63.18, and HOMA = 14.95. The optimum 1EFT was modeled with Contour and Response Surface plots. Conclusion. Based on the two surface response models used in our study, the maximal decrease of visceral fat mass as assessed by measuring echography images of epicardial fat thickness can be obtained by bariatric surgery of persons who are between 31 and 38 year old, have a BMI between 45 and 63 kg/m2 and have a HOMA-IR 34 between 15 and 35. Central Composite Design and a Box-Behnken Design of suitable patient data predicted 35 optimal settings of independent variables for the maximal clinical response of an intervention

Autoimmune Pancreatitis and Treatment Approaches with Case Reports

Objective: In this study, we aimed to review retrospectively the data of 10 patient who were treated and followed-up in our clinic and to review the current approaches in the diagnosis and treatment of autoimmune pancreatitis (AIP).Material and Methods: We reviewed 10 patients retrospectively who were operated on and had the diagnosis of AIP histopathologically in the Ege University School of Medicine Department of General Surgery.Results: Between June 2001-November 2010, 10 patients who were diagnosed as AIP were examined retrospectively. Radiologically, a pancreatic mass was found in the pancreatic head with ultrasound in 7 (70%) of 10 patients and suspicious lesions were identified in the head of the pancreas in 3 (30%) patients. All patients were operated on in our clinic with the preliminary diagnosis of pancreatic head tumor; 8 patients underwent Whipple’s procedure, 1 patient underwent pylorus preserving pancreaticoduodenectomy, and in 1 patient an exploratory pancreatic biopsy (frozen section) was carried out.Conclusion: Autoimmune pancreatitis is a disease with increasing incidence and characterized by lymphoplasmocytic cell infiltration and fibrosis. Patients with a pancreatic mass, if there is an autoimmune disease or chronic pancreatitis suspected in the detailed history, it is necessary to evaluate patients in terms of AIP serologically to protect the patients from an incoorectng diagnosis and morbidity of surgery