Nonparametric estimation of the jump component in financial time series

In this thesis, we analyze nonparametric estimation of Lévy-based models using wavelets methods. As the considered class is restricted to pure-jump Lévy processes, it is sufficient to estimate their Lévy densities. For implementing a wavelet density estimator, it is necessary to setup a preliminary histogram estimator. Simulation studies show that there is an improvement of the wavelet estimator by invoking an optimally selected histogram. The wavelet estimator is based on block-thresholding of empirical coefficients. We conclude with two empirical applications which show that there is a very high arrival rate of small jumps in financial data sets

Relationship between subclinical hypothyroidism and serum homocysteine concentration in premenopausal women

Objective: In our study we aimed to examine serum homocysteinelevels of patients without thyroid dysfunctionswho have high serum anti thyroid peroxidase (anti-TPO)levels and patients with subclinical hypothyroidism whohave high serum thyroid stimulating hormone (TSH) andanti-TPO levels.Methods: One hundred and seven premenopause femaleoutpatients who referred to endocrine clinic of our hospitalwere included in our study. We generated 3 groups. Firstgroup (Control) consists of 53 (50%) patients between theages of 30-40 years. Second group (Euthyroid) consistsof 31 (29%) patients between the ages of 26-49. Thirdgroup (Subclinical Hypothyroidism) consists of 23 (21%)patients between the ages of 33-53 years. Serum totalcholesterol, triglycerides, high density lipoprotein (HDL)levels were measured by Olympus 2700 autoanalyzer.Serum TSH, free T4, anti-TPO and homocysteine levelswere measured by Siemens Immulite 2000 autoanalyzer.Results: In our study, total cholesterol, triglycerides, lowdensity lipoprotein (LDL) and very low density lipoprotein(VLDL) levels were not statistically significantly differentamong the groups. Although serum homocysteine levelsof the third group were higher than the other groups it wasnot statistically significantly different among the groups.Conclusion: Serum homocysteine and lipid levels of patientswith euthyroidism and subclinical hypothyroidismwho have positive anti-TPO levels may be inadequate inassessing the risk of cardiovascular diseases. J Clin ExpInvest 2013; 4 (3): 293-297Key words: Hypothyroidsm, homocysteine, premenopaus

EDTA INDUCED PSEUDOTHROMBOCYTOPENIA IN A PATIENT WITH HEPATITIS A INFECTION

Pseudotrombositopeni kanama riskinde artışa neden olmayan ve trombosit transfüzyonu gerektirmeyen bir iyatrojenik laboratuar fenomenidir. Etilendiaminotetraasetik asid'e (EDTA) bağlı pseudotrombositopeni, otomatik kan sayımında yalancı olarak trombosit sayısındaki azalmayı tanımlamaktadır. Kan örneklerinin EDTA ile antikoagule edilmesi sonucunda normal kişilerde oluşabileceği gibi farklı hastalıkların seyrinde de gözlenebilmektedir. Bu yazıda hepatit A infeksiyonu seyrinde gözlenen bir EDTA bağımlı pseudotrombositopeni olgusu sunulmuştur. Olgu halen devam eden pseudotrombositopeni nedeniyle izlenmektedir. Pseudothrombocytopenia is an iatrogenic laboratory phenomenon that does not increase the risk of bleeding or the need for platelet transfusion. The term ethylenediaminotetraacetic acid (EDTA) induced pseudothrombocytopenia, defines false low platelet count when measured with automatic counters. It may occur in both normal individuals and patients with a variety of diseases when their blood samples are anticoagulated with EDTA. Here we report a patient with EDTA induced pseudothrombocytopenia during the course of hepatitis A infection. The patient is still being followed up with pseudothrombocytopenia

The Diagnostic Value of Brush Cytology Alone and in Combination with Tumor Markers in Pancreaticobiliary Strictures

Aim. Differentiation of malignant and benign strictures constitutes a problem despite the increasing experience of the endoscopists, radiologists, and pathologists. The aim of our study is to determine the factors that affect the efficacy of the ERCP guided brush cytology in PBS and to evaluate its diagnostic success when used alone and together with tumor markers. Method. The data from brush cytologies of 301 PBS patients were collected retrospectively and analyzed. The final diagnosis was approved based on the histological examination of the tissue taken surgically or by other methods. In the absence of a histological diagnosis, the final diagnosis was based on radiological studies or the results of a 12-month clinical follow up. Results. A total of 28 patients were excluded from the study. From the remaining 273 patients 299 samples were analyzed. The sensitivity and the specificity of brush cytology in diagnosing malignancy are 62.4% and 97.7, respectively. The sensitivity of brush cytology increased to 94.1% when combined with CA-19.9 and CA-125. Conclusion. Brush cytology is a useful method in diagnosing pancreaticobiliary strictures. Advanced age, stricture dilatation before sampling, the presence of a mass identified by radiological studies, high levels of CA-19.9, ALT, and total bilirubin increase the sensitivity of brush cytology

The genetic history of the Southern Arc: a bridge between West Asia and Europe

By sequencing 727 ancient individuals from the Southern Arc (Anatolia and its neighbors in Southeastern Europe and West Asia) over 10,000 years, we contextualize its Chalcolithic period and Bronze Age (about 5000 to 1000 BCE), when extensive gene flow entangled it with the Eurasian steppe. Two streams of migration transmitted Caucasus and Anatolian/Levantine ancestry northward, and the Yamnaya pastoralists, formed on the steppe, then spread southward into the Balkans and across the Caucasus into Armenia, where they left numerous patrilineal descendants. Anatolia was transformed by intra–West Asian gene flow, with negligible impact of the later Yamnaya migrations. This contrasts with all other regions where Indo-European languages were spoken, suggesting that the homeland of the Indo-Anatolian language family was in West Asia, with only secondary dispersals of non-Anatolian Indo-Europeans from the steppe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

In vitro/in vivo evaluation of nanoparticular systems in inflammatory bowel disease model

Bu çalışmada, melatonin kullanılarak kolona hedeflendirilmiş, nanopartiküler ilaç taşıyıcı sistemlerin oluşturulması, bunların karakterize edilmesi, hazırlanan formülasyonların in vitro salım çalışmalarının yapılması ve yapay sinir ağı modellemesi sonucunda elde edilen veriler doğrultusunda uygun olduğuna karar verilen formülasyonun, TNBS ile kolit indüklenmiş sıçanlarda kolit üzerindeki etkisinin değerlendirilmesi amaçlanmıştır. Modifiye edilen iyonotopik jelasyon yöntemiyle melatonin yüklü, kalsiyum pektinat nanopartikül formülasyonları hazırlanmıştır. Hazırlanan nanopartikül formülasyonları partikül büyüklüğü, zeta potansiyel, PDI değerleri kullanılarak karakterize edilmiştir, in vitro salım çalışmaları gerçekleştirilmiş ve mukoadezyon özellikleri incelenmiştir. AFM ve TEM teknikleri kullanılarak nanopartiküllerin görüntüsü elde edilmiştir. Yapay sinir ağı modellemesi sonucunda elde edilen veriler doğrultusunda uygun olduğuna karar verilen formülasyon seçilerek in vivo çalışmalarda kullanılmıştır. İn vivo çalışmalarda Wistar erkek sıçanlar kullanılmıştır. TNBS ile kolit oluşturulan sıçanlara, oral ve intrakolonik yoldan 10 mg/kg dozunda MEL yüklü nanopartikül formülasyonu, dört gün süreyle verilmiş ve elde edilen sonuçlar oral ve intrakolonik yoldan boş nanopartikül formülasyonu verilen sıçanlarınki ile karşılaştırılmıştır. Tedavinin sonunda kolon dokusundaki oksidatif parametreler (NOx, MDA ve GSH) ve sitokin düzeyleri (TNF-?, IL-10 ve IL-17) ölçülmüştür. Oral ve intrakolonik yoldan melatonin tedavisi uygulanan gruplarda kolonik NOx ve MDA düzeyleri boş nanopartikül formülasyonu verilen gruplara kıyasla anlamlı olarak azalmış, GSH düzeyleri ise anlamlı olarak artmıştır. Ayrıca proinflamatuvar TNF-?, IL-17 ve antiinflamatuvar IL-10 sitokin düzeyleri ise anlamlı olarak azalmıştır. Histolojik bulgalara göre, oral ve intrakolonik yoldan melatonin yüklü nanopartikül tedavisi uygulanan gruplarda doku iyileşmesinin boş nanopartikül formülasyonu verilen gruplara kıyasla daha iyi olduğu görülmüştür. Elde edilen sonuçlar, hazırlanan melatonin yüklü nanopartikül formülasyonunun, İBH'da oksidatif strese bağlı olarak gelişen kolonik doku hasarında etkili olabileceğini göstermektedir.The aim of this study was to formulate colon targetted nanoparticular drug carrier systems of melatonin, characterization of them, conducting in vitro release studies of the prepared formulations and to determine the effect of the formulation which was found to be suitable as a result of artifical neural network modelling, on TNBS induced colitis in rats. Melatonin loaded calcium pectinate nanoparticle formulations prepared with modified ionotropic gelation method. Prepared nanoparticle formulations characterized by particle size, zeta potential and polydispersity index, the in vitro release studies were performed and mucoadhesion were investigated. AFM and TEM techniques are used to obtain nanoparticle images. The formulation which was found to be suitable as a result of artifical neural network modelling was used in in vivo studies. Wistar male rats were used in in vivo studies. 10 mg/kg melatonin loaded nanoparticle formulation was given oral and intracolonic route to TNBS induced colitis rats for four days. The obtained results are compared with the results of the rats which was given blank nanoparticle formulation. At the end of the treatment, oxidative parameters (NOx, MDA ve GSH) of the colonic tissue and cytokine levels was evaluated. Colonic tissue NOx and MDA levels in the group treated with melatonin by oral and intracolonic route were found to be lower compared to the groups which treated with blank nanoparticle formulation. Colonic tissue GSH levels in the group treated with melatonin by oral and intracolonic route were found to be higher compared to the groups which treated with blank nanoparticle formulation. Also proinflammatory TNF-?, IL-17 levels and antiinflammatory IL-10 levels in the group treated with melatonin by oral and intracolonic route were found to be lower compared to the groups which treated with blank nanoparticle formulation. According to histological findings, the tissue healing in the group treated with melatonin loaded nanoparticle formulation by oral and intracolonic route was found better than the group treated with blank nanoparticle formulation. The results of the experiments showed that, melatonin loaded nanoparticle formulation can be effective in colonic tissue damage which develops due to oxidative stress in IBD

Metabolic and cardiovascular impact of non-functioning adrenal adenomas: a clinical dilemma.

There is growing evidence suggesting a causative relationship between adrenal adenomas and metabolic and cardiovascular deteriorations. Although demonstrated frequently in subjects with subclinical Cushing Syndrome, subjects with non-functioning adrenal adenomas feature a variety of metabolic and cardiovascular consequences. In this review, current data regarding this issue and possible underlying mechanisms have been summarized. (C) 2013 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved

Pervane ve pervane kolu arasındaki etkileşimin havada tutunan uçuş durumu için hesaplamalı yöntemle analiz edilmesi.

This study presents a computational analysis on the interaction between rotor and different rotor frame-arm geometries in hovering flight. The influence of the frame arm on the aerodynamic performance of the rotor is assessed by using commercially available computational fluid dynamics (CFD) solver software ANSYS Inc. Fluent 17. Numerical results are validated for hovering and forward vertical climb flight conditions with thrust and torque measurements conducted on a 16x4 carbon fiber propeller. The thrust and torque measurements were performed in the test section of the low-speed METUWIND C3 wind tunnel at the Rüzgem (Metuwind). After validating the numerical simulations with the thrust and torque measurement results of the 16x4 carbon fiber propeller, four different arm geometries (i.e., Eppler Arm, 25mm cylindrical tube, 25mm square tube, and 25mm square tube with a 10mm slot) are created, and added to the validated CFD model to assess their effect on the aerodynamic performance of the rotors. After validating the numerical simulations with the thrust and torque measurement results of the After validating the thrust and torque measurement results of the 16x4 carbon fiber propeller with the numerical simulations, four different arm geometries (i.e., Eppler Arm, 25mm cylindrical tube, 25mm square tube, and 25mm square tube with a 10mm slot) are created, and added to the validated CFD model to assess their effect on the aerodynamic performance of the rotors.The results of this study reveal that the propeller-Eppler arm configuration has 4.89%, 21.59%, and 5.18% greater propeller efficiency than that of the propeller-cylindrical arm, propeller-square arm, and propeller-slotted square arm configurations, respectively.Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Aerospace Engineering