WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12469/4465

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Citation - WoS: 35
Citation - Scopus: 37
Are Fan Tokens Fan Tokens?
(Academic Press Inc Elsevier Science, 2022) Demir, Ender; Ersan, Oguz; Popesko, Boris
Fan tokens, digital assets providing privileges including rewards and promotions as well as voting rights in polls, recently became highly popular among the football clubs and the (fan) investors. Fan tokens differ from the stocks of football clubs with respect to ownership properties. Fan tokens might be associated with investor mood changes and reaction to match results. This paper aims to explore the impact of football match results on token prices of the clubs. We show that both the losses and wins in the most prestigious European tournament, UEFA Champions League affect the fan token abnormal returns, losses with an effect of a larger magnitude. Domestic matches and Europa League matches are not followed by similar reactions from the investors. Our results are robust to the use of alternative model specifications and various benchmark assets.
Citation - WoS: 5
Citation - Scopus: 7
Calculating Level Densities of Heavy Nuclei by the Shell Model Monte Carlo Method
(Academic Press Inc Elsevier Science, 2014) Alhassid, Yoram; Özen, Cem; Nakada, Hitoshi
The microscopic calculation of nuclear level densities in the presence of correlations is a difficult many-body problem. The shell model Monte Carlo method provides a powerful technique to carry out such calculations using the framework of the configuration-interaction shell model in spaces that are many orders of magnitude larger than spaces that can be treated by conventional methods. We present recent applications of the method to the calculation of level densities and their collective enhancement factors in heavy nuclei. The calculated level densities are in close agreement with experimental data.
Citation - WoS: 16
Citation - Scopus: 16
Detecting Structural Changes Using Wavelets
(Academic Press Inc Elsevier Science, 2015) Yazgan, M. Ege; Ozkan, Harun
We propose a powerful wavelet method to identify structural breaks in the mean of a process. If there is a structural change in the mean the sum of the squared scaling coefficients absorbs more variation leading to unequal weights for the variances of the wavelet and scaling coefficients. We use this feature of wavelets to design a statistical test for changes in the mean of an independently distributed process. We establish the limiting null distribution of our test and demonstrate that our test has good empirical size and substantive power relative to the existing alternatives especially for multiple breaks. (C) 2014 Elsevier Inc. All rights reserved.
Citation - WoS: 85
Citation - Scopus: 89
Electrical and Optical Percolations of Polystyrene Latex-Multiwalled Carbon Nanotube Composites
(Academic Press Inc Elsevier Science, 2010) Kara, Selim; Arda, Ertan; Dolastir, Fahrettin; Pekcan, Önder
Electrical conductivity and optical transmittance properties of polystyrene (PS)-multiwalled carbon nanotube (MWCNT) composite films were investigated. Composite films were prepared by mixing of various mass fractions of MWCNT in PS-water dispersions. After water evaporates powder composite films were annealed at 175 degrees C above the glass transition of PS for 20 min. Photon transmission and two point probe resistivity techniques were employed to determine the variations of the optical and the electrical properties of composites. Transmitted light intensity I(tr) and surface resistivity R(s) were monitored as a function of MWCNT mass fraction (M). It was observed that both the surface resistivity and the optical transparency were decreased by increasing the amount of MWCNT added to the polymeric system. Conductivity and optical results were interpreted according to the classical and site percolation theory respectively. The electrical (sigma) and the optical (op) percolation threshold values and critical exponents were calculated as M(sigma) = 1.8 wt.% M(op) = 0-0.13 wt.% and beta(sigma) = 2.25 beta(op) = 0.32 respectively. (C) 2010 Elsevier Inc. All rights reserved.
Citation - WoS: 57
Citation - Scopus: 65
Esg Performance and Dividend Payout: a Channel Analysis
(Academic Press Inc Elsevier Science, 2023) Bilyay-Erdogan, Seda; Danisman, Gamze Ozturk; Demir, Ender
This paper investigates the impact of environmental, social, and governance (ESG) performance on corporate dividend policy. We employ a panel data set comprised of 1094 non-financial listed firms in 21 European countries from 2002 to 2019. We show that companies with higher ESG performance are likely to pay higher dividends. Our results are robust to alternative variable definitions and specifications and address endogeneity concerns. We next investigate the possible transmission channels through which corporate ESG performance enhances dividend payouts. We present novel evidence that earnings and risk are the two possible channels through which ESG performance augments corporate dividends.
Citation - WoS: 27
Citation - Scopus: 27
Exploiting Heterogeneous Parallelism With the Heterogeneous Programming Library
(Academic Press Inc Elsevier Science, 2013) Vinas, Moises; Bozkuş, Zeki; Fraguela, Basilio B.
While recognition of the advantages of heterogeneous computing is steadily growing the issues of programmability and portability hinder its exploitation. The introduction of the OpenCL standard was a major step forward in that it provides code portability but its interface is even more complex than that of other approaches. In this paper we present the Heterogeneous Programming Library (HPL) which permits the development of heterogeneous applications addressing both portability and programmability while not sacrificing high performance. This is achieved by means of an embedded language and data types provided by the library with which generic computations to be run in heterogeneous devices can be expressed. A comparison in terms of programmability and performance with OpenCL shows that both approaches offer very similar performance while outlining the programmability advantages of HPL. (C) 2013 Elsevier Inc. All rights reserved.
Citation - WoS: 23
Citation - Scopus: 25
Holocene coastal change in the ancient harbor of Yenikapi-Istanbul and its impact on cultural history
(Academic Press Inc Elsevier Science, 2011) Algan, Oya; Yalçın, M. Namık; Özdoğan, Mehmet; Yılmaz, Yücel; Sari, Erol; Kirci-Elmas, Elmas; Yılmaz, Isak; Bulkan, Özlem; Ongan, Demet; Gazioğlu, Cem; Nazik, Atike; Polat, Mehmet Ali; Meriç, Engin
An extensive rescue excavation has been conducted in the ancient harbor of Istanbul (Yenikapi) by the Sea of Marmara revealing a depositional sequence displaying clear evidence of transgression and coastal progradation during the Holocene. The basal layer of this sequence lies at 6 m below the present sea level and contains remains of a Neolithic settlement known to have been present in the area indicating that the sea level at similar to 8-9 cal ka BP was lower than 6 m below present. Sea level advanced to its maximum at similar to 6.8-7 cal ka BP drowning Lykos Stream and forming an inlet at its mouth. After similar to 3 cal ka BP coastal progradation became evident. Subsequent construction of the Byzantine Harbor (Theodosius \4th century AD) created a restricted small basin and accumulation of fine-grained sediments. The sedimentation rate was increased due to coastal progradation and anthropogenic factors during the deposition of coarse-grained sediments at the upper parts of the sequence (7th-9th centuries AD). The harbor was probably abandoned after the 11th century AD by filling up with Lykos Stream detritus and continued seaward migration of the coastline. (C) 2011 University of Washington. Published by Elsevier Inc. All rights reserved.
Citation - WoS: 20
Citation - Scopus: 21
How People Can Become Persuaded by Weak Messages Presented by Credible Communicators: Not All Sleeper Effects Are Created Equal
(Academic Press Inc Elsevier Science, 2017) Albarracin, Dolores; Kumkale, Gökçe Tarcan; Vento, Patrick Poyner-Del
The sleeper effect has been proposed to describe temporal changes in persuasion for messages associated with noncredible sources. The present research introduces a new kind of sleeper effect denoting increases in persuasion for weak messages associated with credible sources. This effect of the source was hypothesized to derive from attending to the message source rather than the message arguments and reconstructing delayed attitudes primarily on the basis of the source information. Findings from three experiments revealed that when the focus of attention was the communicator there was a sleeper effect for the source. Specifically during the time between an immediate follow up and a delayed follow up persuasion increased when credible sources presented weak arguments. In contrast when the focus of attention was the message arguments a traditional sleeper effect emerged. That is persuasion increased when strong arguments were presented by a noncredible communicator. These effects were mediated by relative recall of arguments versus source attributes and replicated with different message topics and lengths of delay. (C) 2016 Published by Elsevier Inc.
Citation - WoS: 1
Citation - Scopus: 1
Invariant Manifolds of Homoclinic Orbits and the Dynamical Consequences of a Super-Homoclinic: a Case Study in R4 With Z2-Symmetry and Integral of Motion
(Academic Press Inc Elsevier Science, 2022) Bakrani, Sajjad; Lamb, Jeroen S. W.; Turaev, Dmitry
We consider a Z(2)-equivariant flow in R-4 with an integral of motion and a hyperbolic equilibrium with a transverse homoclinic orbit Gamma. We provide criteria for the existence of stable and unstable invariant manifolds of Gamma. We prove that if these manifolds intersect transversely, creating a so-called super-homoclinic, then in any neighborhood of this super-homoclinic there exist infinitely many multi-pulse homoclinic loops. An application to a system of coupled nonlinear Schrodinger equations is considered. (C) 2022 The Authors. Published by Elsevier Inc.
Investigation of Novel Nimesulide Derivatives Against Breast Cancer
(Academic Press Inc Elsevier Science, 2025) Birgul, Kaan; Atlihan, Irem; Dere, Damla; Yelekci, Kemal; Tiber, Pinar Mega; Orun, Oya; Kucukguzel, S. Guniz
This study focused on the synthesis of novel nimesulide semicarbazone derivatives and the evaluation of their cytotoxic potential against luminal-A (MCF-7) and triple-negative (MDA-MB-231) breast cancer cell lines. Additionally, their effects on mitochondrial membrane potential (MMP), apoptosis, and mitogen-activated protein kinase (MAPK) pathway modulation were investigated. Breast cancer remains the most prevalent malignancy among women, with luminal-A and triple-negative subtypes posing significant therapeutic challenges due to drug resistance and the lack of effective targeted treatments. The MAPK pathway plays a crucial role in breast cancer progression, making its inhibition a promising therapeutic approach. Non-steroidal anti-inflammatory drugs (NSAIDs), particularly nimesulide, have demonstrated anticancer potential beyond their well-established anti-inflammatory properties. Accordingly, the semicarbazone moiety was incorporated into the molecular scaffold to enhance the antiproliferative efficacy of nimesulide derivatives, as it has been reported to exhibit cytotoxic and apoptosis-inducing effects across various cancer cell lines. A series of nimesulide semicarbazone derivatives (5a-m) were synthesized through multi-step reactions and characterized using elemental analysis, FT-IR, 1H NMR, 13C NMR and Mass spectroscopy (5e). In silico studies were performed to predict their binding affinities to MAPK12. The cytotoxic effects of the synthesized compounds were assessed by determining IC50 values in MCF-7 and MDA-MB-231 cell lines (CCK8 test). Compounds exhibiting strong cytotoxic activity were further examined for their impact on MMP depolarization (JC-1 assay), apoptosis induction (Annexin V-FITC/PI staining), and MAPK pathway modulation (Western blotting of p-ERK and ERK protein). Molecular docking results indicated that the synthesized compounds exhibited favorable interactions with MAPK12, with compound 5e showing one of the highest binding affinity (-9.29 kcal/mol, Ki = 0.154 mu M). Cytotoxicity assays revealed that compound 5e had the lowest IC50 values (11.77 +/- 0.26 mu M in MCF-7; 20.72 +/- 0.25 mu M in MDA-MB-231), demonstrating significantly higher cytotoxicity than nimesulide. JC-1 assays confirmed that compound 5e induced MMP depolarization at higher concentrations, suggesting apoptosis activation. Flow cytometry analysis further validated a substantial increase in apoptotic cell populations following treatment with compound 5e. Western blot results showed a dose-dependent decrease in p-ERK levels in both MCF-7 and MDA-MB-231 cells, confirming MAPK pathway inhibition. These findings support that nimesulide-based semicarbazones, particularly compound 5e, exhibit potent antiproliferative and pro-apoptotic activity via MAPK pathway modulation, offering a promising avenue for the development of targeted breast cancer therapies.
Citation - WoS: 10
Citation - Scopus: 12
On Channel Estimation for Spatial Modulated Systems Over Time-Varying Channels
(Academic Press Inc Elsevier Science, 2015) Acar, Yusuf; Doğan, Hakan; Panayırcı, Erdal
Spatial Modulation (SM) has been proposed recently for multiple-input multiple-output (MIMO) systems to cope with the interchannel interference and to reduce the detection complexity as compared to the conventional MIMO systems. In SM system the data symbols are transmitted by a randomly selected active antenna of a MIMO transmitter to the receiver through a wireless channel. The information is carried both by the data symbol from any signal constellation such as M-ary phase shift keying (M-PSK) or M-ary quadrature amplitude modulation (M-QAM) by the index of the selected antenna. The channel estimation is a critical process at the receiver during the coherent detection of the transmitted symbol and the antenna index randomly selected. Recently the channel estimation of channel for SM systems has been investigated by the recursive least square (RLS) algorithm for only quasi-static fading channels. In this paper a novel channel estimation is proposed for SM systems in the presence of rapidly time-varying channels. The Bayesian mean square error (MSE) bound has been derived as a benchmark and the performance of the proposed approaches is studied in terms of MSE and bit-error rate (BER). Computer simulation results have confirmed that the proposed iterative channel estimation technique has significant BER/MSE performance advantages compared with existing channel estimation algorithm proposed earlier in the literature. (C) 2014 Elsevier Inc. All rights reserved.
Citation - WoS: 22
Citation - Scopus: 25
Secondhand Smoke in Waterpipe Tobacco Venues in Istanbul Moscow and Cairo
(Academic Press Inc Elsevier Science, 2019) Moon, Katherine A.; Magid, Hoda; Torrey, Christine; Rule, Ana M.; Ferguson, Jacqueline; Susan, Jolie; Sun, Zhuolu; Abubaker, Salahaddin; Levshin, Vladimir; Çarkoğlu, Aslı; Radwan, Ghada Nasr; El-Rabbat, Maha; Cohen, Joanna E.; Strickland, Paul; Navas-Acien, Ana; Breysse, Patrick N.
Objective: The prevalence of waterpipe tobacco smoking has risen in recent decades. Controlled studies suggest that waterpipe secondhand smoke (SHS) contains similar or greater quantities of toxicants than cigarette SHS which causes significant morbidity and mortality. Few studies have examined SHS from waterpipe tobacco in real-world settings. The purpose of this study was to quantify SHS exposure levels and describe the characteristics of waterpipe tobacco venues. Methods: In 2012-2014 we conducted cross-sectional surveys of 46 waterpipe tobacco venues (9 in Istanbul 17 in Moscow and 20 in Cairo). We administered venue questionnaires conducted venue observations and sampled indoor air particulate matter (PM2.5) (N=35) carbon monoxide (CO) (N=23) particle-bound polycyclic aromatic hydrocarbons (p-PAHs) (N=31) 4-methylnitrosamino)-1-(3-pyridy1)-1-butanone (NNK) (N-43) and air nicotine (N=46). Results: Venue characteristics and SHS concentrations were highly variable within and between cities. Overall we observed a mean (standard deviation (SD)) of 5 (5) waterpipe smokers and 5 (3) cigarette smokers per venue. The overall median (25th percentile 75th percentile) of venue mean air concentrations was 136 (82 213) mu/m(3) for PM2.5 3.9 (1.7 22) ppm for CO 68 (33 121) ng/m(3) for p-PAHs 1.0 (0.5 1.9) ng/m(3) for NNK and 5.3 (0.7 14) mu g/m(3) for nicotine. PM2.5 CO and p-PAHs concentrations were generally higher in venues with more waterpipe smokers and cigarette smokers although associations were not statistically significant. Conclusion: High concentrations of SHS constituents known to cause health effects indicate that indoor air quality in waterpipe tobacco venues may adversely affect the health of employees and customers. (C) 2015 Elsevier Inc. All rights reserved.
Citation - WoS: 13
Citation - Scopus: 16
A Short Note on the Geo-Archeological Significance of the Ancient Theodosius Harbour (istanbul Turkey)
(Academic Press Inc Elsevier Science, 2009) Algan, Oya; Yalçın, M. Namık; Özdoğan, Mehmet; Yılmaz, İsak; Sarı, Erol; Kirci-Elmas, Elmas; Ongan, Demet; Bulkan-Yeşiladalı, Özlem; Yılmaz, Yücel; Karamut, Ismail
The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour at Istanbul contains the records of sea level environmental changes and the Cultural history of the region The cobbles at the base of the sequence include archaeological remnants of Neolithic Culture that settled in the at ea between 8.4 and 73 (14)C ka BP and are located at 6 m below the present sea level The sediments representing a coastal environment indicate that the area was used as a harbour from AD 4th to at least the I I ill century and were filled by the sediments derived from Lykos Stream after 11th Century (C) 2009 University of Washington Published by Elsevier Inc All rights reserved
Citation - WoS: 9
Citation - Scopus: 9
Smoke-Free Turkey: Evaluation of Outdoor Areas of Public Places
(Academic Press Inc Elsevier Science, 2019) Kaplan, Bekir; Grau-Perez, Maria; Çarkoğlu, Aslı; Ergör, Gül; Hayran, Mutlu; Navas-Acien, Ana; Cohen, Joanna E.
Significance: Secondhand tobacco smoke (SHS) exposure is a major cause of morbidity and mortality around the world. The objective of this study was to evaluate the presence of smoking in outdoor areas of public places in three largest Turkish cities (Istanbul Ankara and Izmir). Method: For this cross-sectional observational study the Turkish Statistical Institute randomly selected 10 sampling points in each city. Around each sampling point fieldworkers visited the closest bars/nightclubs cafes government buildings hospitals restaurants schools shopping malls traditional coffee houses universities children's playgrounds parks and open markets. We observed smoking ashtrays and cigarette butts at the outdoor areas of public venues within the urban districts of each city. The fieldwork was conducted in April–May 2016. Results: 477 venues were observed covering 1017 outdoor locations in which 17737 people were observed. Smoking in outdoor areas ranged from 3.7% around schools to 90% in open markets. Ashtrays were almost ubiquitous in hospitals (95.6%) shopping malls (92.0%) and universities (90.9%). Cigarette butts were more often observed in open markets (100%) shopping malls (96%) universities (95.5%) and parks (93.3%). Smoking at outdoor areas around schools was significantly lower than around other venues. Conclusion: Smoking in outdoor areas was common in most public places in Turkey except schools. The current indoor SHS legislation should be extended to cover adjacent outdoor areas of public venues in order to effectively protect people from SHS exposure in Turkey. © 2019 The Authors

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