Reward-to-risk ratios in Turkish financial markets

This paper investigates how reward-to-risk ratios compare among various government debt security (GDS) indices and sector indices in the Istanbul Stock Exchange. Risk is measured by either standard deviation or nonparametric and parametric value at risk. We find that the GDS indices have higher reward-to-risk ratios compared to the sector indices. GDS indices with longer maturities have lower reward-to-risk ratios and this reduction is especially pronounced when the ratios take downside risk into account. The reward-to-risk rankings for the sector indices are similar for each measure and the results are robust to currency conversion

Risk-adjusted performances of world equity indices

This paper investigates whether equity indices of 24 emerging and 28 developed markets compensate their investors equally after taking risk into account. We place special emphasis on downside risk by calculating both nonparametric and parametric value at risk. We find that when all 52 markets are ranked based on their alternative reward-to-risk ratios, almost all of the countries in the top quartile are emerging markets whereas almost all of the countries in the bottom quartile are developed markets. These results are supported by the finding that pooled means of the reward-to-risk ratios are significantly higher for emerging markets compared to those of developed markets. Focusing on the period after the initiation of the recent financial crisis reveals that, although both developed and emerging markets suffered in terms of generating higher returns per unit risk, emerging markets continued to outperform developed markets and the outperformance became more pronounced

Reward-to-risk ratios in Turkish financial markets (Türkiye finans piyasalarında getiri-risk rasyoları)

This paper investigates how reward-to-risk ratios compare among various government debt security (GDS) indices and sector indices in the Istanbul Stock Exchange. Risk is measured by either standard deviation or nonparametric and parametric value at risk. We find that the GDS indices have higher reward-to-risk ratios compared to the sector indices. GDS indices with longer maturities have lower reward-to-risk ratios and this reduction is especially pronounced when the ratios take downside risk into account. The reward-to-risk rankings for the sector indices are similar for each measure and the results are robust to currency conversion

MCTP is an ER-resident calcium sensor that stabilizes synaptic transmission and homeostatic plasticity.

Presynaptic homeostatic plasticity (PHP) controls synaptic transmission in organisms from Drosophila to human and is hypothesized to be relevant to the cause of human disease. However, the underlying molecular mechanisms of PHP are just emerging and direct disease associations remain obscure. In a forward genetic screen for mutations that block PHP we identified mctp (Multiple C2 Domain Proteins with Two Transmembrane Regions). Here we show that MCTP localizes to the membranes of the endoplasmic reticulum (ER) that elaborate throughout the soma, dendrites, axon and presynaptic terminal. Then, we demonstrate that MCTP functions downstream of presynaptic calcium influx with separable activities to stabilize baseline transmission, short-term release dynamics and PHP. Notably, PHP specifically requires the calcium coordinating residues in each of the three C2 domains of MCTP. Thus, we propose MCTP as a novel, ER-localized calcium sensor and a source of calcium-dependent feedback for the homeostatic stabilization of neurotransmission

Cylindrically Symmetric Vacuum Solutions in Higher Dimensional Brans-Dicke Theory

Higher dimensional, static, cylindrically symmetric vacuum solutions with and without a cosmological constant in the Brans-Dicke theory are presented. We show that, for a negative cosmological constant and for specific values of the parameters, a particular subclass of these solutions include higher dimensional topological black hole-type solutions with a flat horizon topology. We briefly extend our discussion to stationary vacuum and $\Lambda-$vacuum solutions.Comment: V3: Published Versio

Value of preoperative spirometry to predict postoperative pulmonary complications

AbstractIn order to determine the incidence of postoperative pulmonary complications (POPC) and the value of preoperative spirometry to predict pulmonary complications after upper abdominal surgery, 24 women and 36 men (total 60 patients) were studied prospectively (mean age 48·3 years). On the day before the operation and for 15 days after the operation, each patients's respiratory status was assessed by clinical examination, chest radiography, spirometry and blood gas analysis, and patients were monitored for pulmonary complications by a chest physician and a surgeon independently. In this study, postoperative pulmonary complications developed in 21 (35%) patients (pneumonia in 10 patients, bronchitis in nine patients, atelectasis in one patient, pulmonary embolism in one patient). Of 31 patients with abnormal preoperative spirometry, 14 (45·2%) patients showed complications, whereas among 29 patients with normal preoperative spirometry, 7 (24·1%) patients showed complications (P<0·05). The incidence of POPC was higher in patients with advanced age, smoking, preoperative abnormal findings obtained from physical examination of the chest, higher ASA class and longer duration of operation. The sensitivity (0·76) and specificity (0·79) of abnormal preoperative findings obtained from physical examination to predict POPC were higher than abnormal preoperative spirometry (0·67 and 0·56 retrospectively). There was no significant difference between patients with and without pulmonary complications in regard to weight, serum albumin, type of incision, incidence of abnormal preoperative blood gases and duration of postoperative hospital stay. We conclude that POPC is still a serious cause of postoperative morbidity. Multiple risk factors include preoperative abnormal spirometry responsible for development of POPC. If used alone, spirometry has limited clinical value as a screening test to predict POPC after upper abdominal surgery

Nash Bargaining in Ordinal Environments

Abstract We analyze the implications o