Time-Varying Structure of the Optimal Hedge Ratio for Emerging Markets

Emerging markets are more exposed to risk than developed markets. Therefore, they require risk management using futures market instruments. This study aims to determine the hedging effectiveness of the spot index market risks in the stock index futures market in Brazil, Russia, India, South Africa, and Turkey. Measuring the hedging effectiveness level of futures markets is vital for these countries because investors must remain in the stock markets for the sustainability of the financial markets and economies. Weekly closing data for the period from January 2009 to October 2021 were analyzed via a dynamic method referred to as flexible least squares (FLS). Although the FLS results show that futures transactions provide high hedging effectiveness for all countries within the scope of this study, country-specific conditions may reduce the hedging effectiveness

Betonarme Bir Okul Binasının 2018 Deprem Yönetmeliğine Göre İncelenmesi

Bu çalışmada ülkemiz toprak alanlarının büyük bir çoğunluğu deprem bölgesinde olması nedeniyle Çevre ve Şehircilik Bakanlığı, deprem etkisi altında yeni binaların tasarımında ve mevcut binaların değerlendirilmesinde değişiklikler yaparak depreme dayanıklı yapıların inşa edilmesini hedeflemektedir. Bu amaçla 2018 Deprem yönetmeliği hazırlanmıştır. Yönetmelikte, mevcut binaların zemin özelliklerinin nasıl belirleneceği belirtilmiştir. Bu kapsamda, zemin grupları taşıma gücü açısından en yüksekten en düşüğe doğru A, B, C, D, E, F olarak 6 farklı grupta tanımlanmıştır. Bu çalışmada, 1999 Marmara ve Düzce depremlerinden etkilenmiş ve taşıma gücü yüksek bir zeminde inşa edilmiş bir okul binasının deprem performans analizi yapılmıştır. Binadaki taşıyıcı elemanların kapasiteleri belirlenmiş ve deprem dayanımları değerlendirilmiştir. Binanın içinde ve dışında temel muayene çukurları açılarak temel şekli ve boyutları belirlenmiştir. Sahada zeminin taşıma gücü ve bazı özelliklerin belirlenmesi amacıyla 3 adet sondaj kuyusu açılmıştır. Binanın taşıyıcı elemanları üzerinde donatı çap ve paspayları ölçülerek kolon ve kirişlerden yönetmelikte belirtilen sayıda karot numuneleri alınarak laboratuar ortamında beton basınç dayanımları bulunmuştur. Proje verilerinden elde edilen bilgiler 2018 yönetmeliğine göre “STA4-V14.1”  paket programı ile analiz edilmiştir

Common polymorphisms of growth hormone: Growth hormone receptor axis in Turkish children with short stature

Objective: A single-nucleotide polymorphism of the growth hormone 1 gene, GH1IVS4+90A>T (rs2665802), associated with short stature and a polymorphism of the growth hormone receptor gene, exon 3 deleted variant, associated with increased responsiveness to growth hormone have been reported previously. We aimed to investigate the frequency of both polymorphisms and their correlation to height in Turkish short children. Also, we aimed to evaluate the effect of exon 3 deleted variant on response to 1-year growth hormone therapy. Materials and Methods: Children with idiopathic isolated growth hormone deficiency (n = 39) and with idiopathic short stature (n = 10) and 50 control subjects were evaluated for anthropo-metric parameters, annual growth velocity, and annual height gain. Growth hormone receptor gene polymorphisms were analyzed via multiplex polymerase chain reaction; growth hormone 1 gene polymorphism was analyzed via polymerase chain reaction and single-strand confor-mation polymorphism techniques. Results: The frequency of genotypes carrying the “A” allele was not significantly higher in the idiopathic isolated growth hormone deficiency group than in the idiopathic short stature and control groups (P = .03 for each). The exon 3 deleted variant genotype was significantly lower in the idiopathic short stature group compared to the control group (P = .01). There was no effect of exon 3 deleted variant, on response to the first-year growth hormone therapy. Conclusion: In Turkish population, no correlation was found between the “A” allele of GH1IVS4+90A>T polymorphism and idiopathic isolated growth hormone deficiency and short stature, and a significant negative correlation was found between exon 3 deleted variant and idiopathic short stature and short stature. Exon 3 deleted variant has no effect on response to growth hormone treatment.Istanbul Universit

Brain Perfusion MRI Findings in Patients with Behcet's Disease

Objective. To search brain perfusion MRI (pMRI) changes in Behcet's disease (BD) with or without neurological involvement. Materials and Method. The pMRI were performed in 34 patients with BD and 16 healthy controls. Based on neurologic examination and post-contrast MRI, 12 patients were classified as Neuro-Behcet (group 1, NBD) and 22 patients as BD without neurological involvement (group 2). Mean transit time (MTT), time to peak (TTP), relative cerebral blood volume (rCBV), and relative cerebral blood flow (rCBF) were obtained and compared to those of healthy control group (group 3). Results. There was a significant difference in the MTT and rCBF within the pons and parietal cortex in groups 1 and 2. rCBV increased in cerebral pedicle in group 1 compared with groups 2 and 3. In the temporal lobe white matter, prolonged MTT and decreased rCBF were found in groups 1 and 2. In the corpus striatum, internal capsule, and periventricular white matter, rCBF increased in group 1 compared with group 3 and decreased in groups 1 and 2. Conclusion. Brain pMRI is a very sensitive method to detect brain involvement in patients with BD and aids the clinical diagnosis of NBD, especially in patients with negative MRI findings

The effect of carbon monoxide releasing molecule-2 (Corm-2) on healing of ischemic colon anastomosis in rats

Background/aim: Ischemia on the colon wall negatively affects healing of anastomosis. We were aimed to evaluate the effects of carbon monoxide releasing molecule-2 (CORM-2) on the healing of anastomosis in a rat model of the ischemic colon. Materials and methods: In this prospective study a total of 60 rats were randomly divided into three groups as colon transection and end-to-end anastomosis (Group I), colon transection, and end-to-end anastomosis following the induction of ischemia (Group II), and colon transection and end-to-end anastomosis following the induction of ischemia and treated with daily intraperitoneal administration of CORM-2 (Group III). Each group was also divided into two equal subgroups as postoperative 3rd and 7th day. Postoperative healing of anastomoses was evaluated by anastomosis burst pressure (ABP), tissue biomarkers including hydroxyproline (HP), malondialdehyde (MDA), glutathione (GSH), and histopathological findings. Results: In the ischemic group treated with CORM-2, lower MDA and higher HP levels were observed in comparison to the untreated ischemic group on the 3rd day. GSH and HP levels were higher and MDA levels was lower in the ischemic rats treated with CORM-2 than in the ischemic untreated rats on the 7th day. In the ischemic group treated with CORM-2, the mucosal epithelial score decreased and the neoangiogenesis score increased compared to the untreated rats on the 7th day. Conclusion: In ischemic colon anastomosis, reduces cell destruction by suppressing the oxidative reaction, and strengthening the antioxidative mechanisms of the cells. It also increases collagen formation, epithelial development, and neoangiogenesis

HALKA AÇIK FİRMALARIN BETA KATSAYILARININ REGRESYON MODELİ İLE TESPİTİ VE HALKA AÇIK OLMAYAN FİRMALARA YÖNELİK UYGULANABİLİRLİĞİ

Halka açık olmayan firmaların değerinin tespitinde, mali tablolardan yola çıkılarak bir takım önermeler ve varsayımlar altında değerin tespiti mümkün olabilmektedir. Ancak, bu firmaların özsermaye maliyetlerinin tespitinde önemli bir sorunla karşılaşılmaktadır. Halka açık olmayan firmaların özsermaye maliyetleri Sermaye Varlıklarını Fiyatlandırma Modeli (Capital Assets Pricing Model-CAPM) kullanılarak hesaplanmak istendiğinde, beta katsayılarının tespitinde zorluklar yaşanmaktadır. Çalışmada, bu zorluk dikkate alınarak, öncelikle halka açık firmaların mali tablo değişkenleri ile beta katsayıları arasındaki ilişki regresyon modeli yardımıyla tespit edilmeye çalışılmaktadır. Daha sonrasında, ilgili model halka açık olan firmaların verileri kullanılarak test edilmekte ve halka açık olmayan firmalar üzerinde uygulanmaktadır

Increased oxidative stress is associated with insulin resistance and infertility in polycystic ovary syndrome

Objectives: The present study aims to investigate the role of oxidant-antioxidant status in young women with polycystic ovary syndrome (PCOS).Material and methods: Seventy-one women with PCOS and 53 healthy controls are compared in aspect of demographic characteristics, biochemical data, hormones, and oxidant-antioxidant status.Results: The PCOS group had significantly lower zinc, higher malondialdehyde and gluthathione peroxidase and lower serum catalase levels than the control group (p = 0.016, p < 0.001, p = 0.043 and p = 0.025 respectively). The PCOS patients with IR had significantly higher malondialdehyde, lower catalase and serum zinc levels than the PCOS patients without IR (p = 0.015, p = 0.010, p = 0.001 respectively). The infertile PCOS patients had significantly higher malondialdehyde, lower catalase and serum zinc levels than the fertile PCOS patients (p = 0.022, p = 0.045,p = 0.001 respectively). There was a statistically significant and positive correlation between HOMA-IR and malondialdehyde values (r = 0.523, p = 0.001), between HOMA-IR and glutathione peroxidase values (r = 0.468, p = 0.001) and between HOMA-IR and zinc values (r = 0.601, p = 0.001). There was a statistically significant and negative correlation between HOMA-IR and catalase values (r = –0.493, p = 0.001).Conclusions: The patients with PCOS are under oxidative stress and this oxidative stress seems to be the highest in patients with IR and with infertility. Despite the prominent increase in the oxidative stress, there was a variation in the antioxidant response