Diversification and bank stability in the GCC

This study examines bank diversification strategies and links to financial sector stability. Using a sample of listed and unlisted banks operating in the Gulf Cooperation Council (GCC) countries over 2001 to 2014 we investigate the diversification features of conventional and Islamic banks. Our main finding overall is that income or asset diversification does not enhance bank stability. However, there is evidence of a non-linear relationship between non-interest (non-financing) income and stability indicating that banks are able to reduce risk at higher levels of diversification. Conventional banks appear to be more adversely impacted on the risk side than Islamic banks. We also find that factors such as improved institutional quality, macroeconomic conditions, and other bank-specific factors motivate greater stability.Scopu

Long range dependence in an emerging stock market’s sectors: volatility modelling and VaR forecasting

This study evaluates the sector risk of the Qatar Stock Exchange (QSE), a recently upgraded emerging stock market, using value-at-risk models for the 7 January 2007–18 October 2015 period. After providing evidence for true long memory in volatility using the log-likelihood profile test of Qu and splitting the sample and dth differentiation tests of Shimotsu, we compare the FIGARCH, HYGARCH and FIAPARCH models under normal, Student-t and skewed-t innovation distributions based on in and out-of-sample VaR forecasts. The empirical results show that the skewed Student-t FIGARCH model generates the most accurate prediction of one-day-VaR forecasts. The policy implications for portfolio managers are also discussed. 2017 Informa UK Limited, trading as Taylor & Francis Group.Scopu

Concomitant ependymoma and schwannoma of the lumbar spine without neurofibromatosis

The coexistence of 2 or more different tumors of the central neural axis has been defined and is well known in patients with neurofibromatosis-2 (NF-2), an inherited autosomal dominant disorder caused by defects in chromosome 22. The presence of multiple histologically different spinal tumors in the absence of NF-2 is extremely rare, however. The authors describe a patient with backache, in whom an ependymoma and a schwannoma of the lumbar spine were found in the absence of NF-2

Acute formation of lumbar discal cyst: what is the mechanism?

Lumbar discal cysts are extremely rare pathologies, with only few reports describing these lesions in the literature. Moreover, their definite pathogenesis is still unknown, with proposed theories based on radialogic and histologic findings. In this report, the authors present an acute formation of a discal cyst, which is reported for the first time. Also, we center our case on the discussion of the possible pathogenesis. Also, this is the first case of discal cyst reported in Turkey. A 67-year-old woman, whose complaints, and clinical and radiological findings demonstrated lumbar disc herniation with acute Modic 1 degererative changes of the adjacent end plates of L3-4 level. After medical and physical therapies, follow-up lumbar MRI has been taken to demonstrate a discal cyst formation on the adjacent intervertebral disc, showed cranially migrated cyst superior posterior on herniated disc, in 2 weeks period. The patient was treated by microsurgical resection of the cyst, and her complaints resolved completely

Extended endoscopic endonasal approach to the pterygopalatine fossa: anatomic study

Aim Our aim in this study was to recognize the endoscopic anatomy of the pterygopalatine fossa (PPF) and the anatomic variations of the related neurovascular structures, to define the endoscopic endonasal approach to this region