Purpose-The objective of this paper is to test the validity of Fama and French (2015) five factor model in Istanbul Stock Exchange (ISE) and to determine whether the value factor is redundant in the model. Methodology -To that end, Fama-French five factor model is primarily tested, which is composed of market, firm size, value, profitability and investment factors. Afterwards, the value factor is excluded from the model and the empirical performance of two models are compared. Multiple regression analysis is carried out by using time series data from July 2009 to June 2015. Besides that, GRS-F test is applied to determine the pricing errors in models. Findings-The results show that Fama-French five factor model can be used in ISE in explaining the variation of returns, although the factor returns are lower in comparison with Fama and French (2015) findings. Specifically, the size premium is considerably lower attained. On the other hand, GRS-F test proves there is no pricing error in the model. Conclusion-Finally, the model is found viable in ISE between the period of July 2009 and June 2015. It is further found that the value factor is not redundant in the Fama-French five factor model.

No abstract

Implementation of the Haemophilus influenzae type B (Hib) conjugate vaccine brought about a reduction in the number of cases and morbidity from type B but an increase in nontypeable strain infections. Nontypeable Haemophilus influenzae (NTHi) commonly colonizes children’s upper respiratory tract and causes otitis media, sinusitis, and bronchitis. Invasive NTHi diseases, such as meningitis and septicemia, have rarely been reported. Herein, we discuss a previously healthy, fully immunized 3-year-old girl presented with otitis media and mastoiditis leading to meningitis caused by NTHi complicated with central venous thrombosis. She was treated with antibiotics, mastoidectomy and ventilation tube insertion, and anticoagulation therapy and recovered uneventfully. Through this case, we wish to share our unique clinical experience that NTHi should be born in mind as a potential pathogen that can cause meningitis in previously healthy children, which may be helpful in future cases.

The purpose of the study is to measure the conjoint effect of investment strategy based on gross profitability and 52-week high in Borsa İstanbul for the period 2007-2016. The strategy suggests the investors can profit when they take a long position on stocks with high gross profitability and 52-week high, and short position on stocks with low gross profitability and 52-week high. The portfolio method is used in the analysis. The portfolios sorted on 52-week high provide premium but statistically insignificant whereas gross profitability premium is found positively significant. Besides that, the seasonality of profitability returns is observed, though it is weak. When the strategies are analyzed together, the findings exhibit no superior performance of combined strategy despite of positive premium. It may stem from 52-week high effect that is employed as an alternative measure of momentum. This study exhibits a new evidence in the context of the joint effect of strategies. It's considered that forthcoming researches might focus on the combined performances of the other strategies also by employing alternative measures.

Sermaye varlıklarını fiyatlama modelinin (CAPM), hisse senedi getiri değişimlerinin tümünü açıklamakta yetersiz kalması ve modele yönelik yapılan eleştiriler (Roll, 1977; Fama ve French, 2004) daha iyi modellere olan ihtiyacı beraberinde getirmiştir. Özellikle Fama ve French (1993, 1996)'in firma büyüklüğü ve defter değeri piyasa değeri oranının (D/P oranı) hisse senedi getirileri üzerinde etkili faktörler olduğunu öne sürmesi, üç faktörlü yeni bir modeli ortaya çıkarmıştır. Ancak Fama-French üç faktör modeli de getiri değişimlerinin tümünü açıklamakta yetersiz bulunmuştur. Dolayısıyla tek bir model tarafından getiri değişimlerinin tümünün açıklanamıyor olması, getiriler üzerinde etkili olan yeni faktörlere olan gereksinimi yadsınamaz kılmıştır. Fama-French üç faktör modelinin ardından momentum ve likidite gibi getiriler üzerinde etkili olduğu ileri sürülen değişkenler eklenerek yeni modeller (Carhart dört faktör modeli, Pastor-Stambaugh modeli gibi) geliştirilmiştir.Fama ve French (1993: 55) üç faktörlü modeli ortaya koyduğu çalışmalarında, karlılık, yatırımlar ve diğer değişkenler ile ilgili getiri değişimlerinin ileriki çalışmaların konusu olabileceğini belirtmiştir. Son dönemlerde, yatırım ve karlılık değişkenlerinin hisse senedi beklenen getirilerini tahmin gücü olup-olmadığı üzerinde çalışmalar yoğunlaşmıştır (