The Effect of Macroeconomic Factors on Stock Returns: A Study of Turkey and Emerging Markets

Although there are many studies in the literature that investigate the relationship between stock returns and macroeconomic factors in the United States and other advanced economies, the number of studies that investigate this relationship in emerging market economies is astonishingly small. Hence, the main purpose of this study is to analyze the impact of macroeconomic factors on stock returns in emerging market economies using panel data. The study covers the period between 1996 and 2006. According to the empirical results of this study, it has been observed that stock returns are affected by exchange rates, inflation rates and the S&P 500 Index while the returns are not affected by interest rate, gross domestic product, money supply and oil prices in a statistically significant manner.Stock Returns, Macroeconomic Factors, Panel Data Analysis

Battery recycling by hydrometallurgy : evaluation of simultaneous treatment of several cell systems

A research work has being carried out aiming at evaluating the possibility of treating simultaneously several electrochemical systems of spent batteries using the same process, in order to overcome the high costs and difficulties of selective collection and sorting. Zn-MnO2 systems, representing more than 75% of portable battery market, shall be treated in dedicated processes. The treatment assessment using a single hydrometallurgical process of the other major systems (NiCd, NiMH and Li-ion), having Ni and Co as main metals, was the aim of the research work here reported. Sulfuric acid leaching was demonstrated to be adequate for dissolving more than 90% of the metals of interest contained in batteries. The subsequent separation of metals by solvent extraction, using organophosphorous extractants like DEHPA and Cyanex 272, allowed the production of pure solutions of rare earths, cadmium/manganese, cobalt, nickel and lithium, enabling their further recoverin

Determinants of dividend payout decisions : a dynamic panel data analysis of Turkish stock market

This study analyzes the firm-specific factors affecting the dividend payout decisions of the companies whose shares are traded on the Borsa Istanbul stock exchange. To this end, the dynamic panel regression is applied to 853 observations of yearly average of 106 companies listed on the Borsa Istanbul between 2009 and 2015. According to results from the Arellano–Bover/Blunder-Bond two-step system generalized method of moments, a statistically significant positive effect on dividend payout was found in the relationship between the dividend payout of the previous year, the company’s return on equity and the market value/book value ratio, liquidity and the company’s size. The demonstration of a positive relationship between dividend payout and return on equity supports the free cash flow hypothesis and the positive relationship with the previous year’s dividend payout ratio supports the dividend smoothing hypothesis for Turkey

The effects of different weaning modes on the endocrine stress response

INTRODUCTION: The aim of the present study was to investigate the effects of the stress response on plasma insulin, cortisol, glucose, and urinary vanilmandelic acid during weaning and after extubation, using pressure support (PS), continuous positive airway pressure (CPAP) and T-piece modes. METHODS: Sixty patients were randomly divided into three groups (n = 20). The PS group received FiO(2 )≤ 0.4, PS ≤ 10 cmH(2)O, and positive end expiratory pressure ≤ 5 cmH(2)O for 2 hours. The CPAP group was given FiO(2 )≤ 0.4 and CPAP 5 ≤ cmH(2)O for 2 hours. The T-piece group (group T) received 4 l/min oxygen via a T-piece for 2 hours. After 1 hour and 2 hours in their respective weaning modes, blood and urine samples were taken for insulin, cortisol, glucose and vanilmandelic acid measurements. Forty-eight hours after extubation, blood and urine samples were again taken. RESULTS: Plasma insulin was greater in group T than in the PS and CPAP groups (P < 0.01 and P < 0.01). The plasma cortisol concentration was greater in group T than in group PS during weaning (P < 0.05) and after extubation (P < 0.05). Blood glucose concentrations were greater in group T than in the other groups (both P < 0.01) both during weaning and post extubation. Urine vanilmandelic acid was greater in group T than in the other groups during weaning and after extubation (both P < 0.001). CONCLUSION: Weaning via the T-piece caused a greater stress response than the PS and CPAP modes

Advances in powder bed based Additive Manufacturing of metal-glass-hybrid-components

As powder bed based additive manufacturing (AM) is gaining more traction in the research and industry, significant efforts are made to expand the capability of AM in combining different materials. Conventionally, multiple materials, sealants and processes are necessary in order to join metal and glasses in assemblies. The development of a single-step process for vacuum-tight and strong bonding between glass and metal could drastically reduce the part count and assembly cost. This paper investigates the feasibility of joining the iron-nickel-cobalt alloy Kovar with borosilicate glass. The powder bed fusion by laser beam is used to melt Kovar structures directly onto glass substrates. Suitable process parameter for an iron-silicon-oxide material-bonding layer of 3 µm thickness were developed using design of experiments. With an energy input of 333 J/mm3 for the initial layer and 60 J/mm3 for the bulk structure, tensile testing of the metal-glass-connection revealed bonding forces up to 0.5 MPa

Evaluating Steady-State Visually Evoked Potentials-Based Brain-Computer Interface System Using Wavelet Features and Various Machine Learning Methods

Steady-state visual evoked potentials (SSVEPs) have been designated to be appropriate and are in use in many areas such as clinical neuroscience, cognitive science, and engineering. SSVEPs have become popular recently, due to their advantages including high bit rate, simple system structure and short training time. To design SSVEP-based BCI system, signal processing methods appropriate to the signal structure should be applied. One of the most appropriate signal processing methods of these non-stationary signals is the Wavelet Transform. In this study, we investigated both the effect of choosing a mother wavelet function and the most successful combination of classifier algorithm, wavelet features, and frequency pairs assigned to BCI commands. SSVEP signals that were recorded at seven different stimulus frequencies (6–6.5 – 7 – 7.5 – 8.2 – 9.3 – 10 Hz) were used in this study. A total of 115 features were extracted from time, frequency, and time-frequency domains. These features were classified by a total of seven different classification processes. Classification evaluation was presented with the 5-fold cross-validation method and accuracy values. According to the results, (I) the most successful wavelet function was Haar wavelet, (II) the most successful classifier was Ensemble Learning, (III) using the feature vector consisting of energy, entropy, and variance features yielded higher accuracy than using one of these features alone, and (IV) the highest performances were obtained in the frequency pairs with “6–10”, “6.5–10”, “7–10”, and “7.5–10” Hz

Bank efficiency and non-performing loans: Evidence from Turkey

This study analyses technical and allocative efficiencies in Turkish banks from December 2002 to December 2017, under the assumption of constant returns to scale. We apply a modified version of the Data Envelopment Analysis (DEA) approach introduced by Aparico et al. (2015), which employs a directional distance model to provide estimates of efficiency, with a focus on Non-Performing Loans (NPLs) as an undesirable output. In addition, we examine the determinants of efficiency by applying quantile regressions to panel data. The results obtained support the thesis that NPLs exert a negative impact in terms of technical efficiency, which confirms the “bad management” hypothesis in the banking sector. We also find that the level of efficiency of Turkish banks differs, depending on the ownership structure in place