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Electromagnetic Interactions of Heavy Ions at Small Impact Parameters and Lepton Pair Productions
(Institute of Physics Publishing, 2011) Güçlü, Mehmet Cem; Yılmaz Şengül, Melek
In peripheral collisions the strong electromagnetic fields are produced since the fully stripped heavy ions moves at ultra-relativistic velocities. Lepton pairs especially the electron-positron pairs are the result of this collisions. At the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) virtual photons produce many particles such as electron-positron pairs heavy lepton (muons and tauons) pairs magnetic monopoles W-pairs b-quark pairs and possibly the Higgs. At small impact parameters the colliding nuclei make peripheral collisions photon fluxes are very large and these are responsible for the multiple photonuclear interactions. Free pair productions bound free pair productions and nuclear Coulomb excitations are important examples of such interactions and these processes play important roles in the beam luminosity at RHIC and LHC. Here we obtained bound free electron-positron pair production with nuclear breakup for heavy ion collisions at RHIC and LHC.
Citation - Scopus: 57
Introduction: Orienting Istanbul-Cultural Capital of Europe?
(Routledge Journals Taylor & Francis Ltd, 2010) Göktürk, Deniz; Soysal, Levent; Türeli, Ipek
[Abstract Not Available]
Cezalandırılabilirliğin Objektif Koşulları
(İstanbul Üniversitesi Hukuk Fakültesi, 2010) Kangal, Zeynel T.
[Abstract Not Available]
Citation - WoS: 1
Citation - Scopus: 1
Across Dimensions: Two- and Three-Dimensional Phase Transitions From the Iterative Renormalization-Group Theory of Chains
(2020) Keçoğlu, İbrahim; Berker, A. Nihat
Sharp two- and three-dimensional phase transitional magnetization curves are obtained by an iterative renormalization-group coupling of Ising chains, which are solved exactly. The chains by themselves do not have a phase transition or nonzero magnetization, but the method reflects crossover from temperaturelike to fieldlike renormalization-group flows as the mechanism for the higher-dimensional phase transitions. The magnetization of each chain acts, via the interaction constant, as a magnetic field on its neighboring chains, thus entering its renormalization-group calculation. The method is highly flexible for wide application.
Citation - WoS: 17
Citation - Scopus: 17
The Stage: a Space for Queer Subjectification in Contemporary Turkey
(Routledge Journals Taylor & Francis Ltd, 2012) Selen, Eser
This article focuses on the role of the stage in complex modes of gender performativity in the work of three Turkish performers: Zeki Muren (1931-1996) Bulent Ersoy (b. 1952) and Seyfi Dursunoglu (b. 1932) a.k.a. Huysuz Virjin [Cranky Virgin]. These three I suggest are the pioneers of contemporary Turkish queer performance. Their performances - both on-and off-stage - are validated through a reiterative absence of queerness in their everyday lives and stand in the midst of various negotiations between queers and the secular Islamic nation-state in Turkey. In the works of Muren Ersoy and Huysuz the stage is suggestive of a space where queerness can be managed. It is a contested space that does at least allow for the communication of queer ideas to a wider audience. I discuss the works of these three performers as three variations of queerness in Turkey in relation to different eras and different political climates that are directly related to the nation-state's desire to perform modernity. While explicating complicated modes of gender performativity I consider the stage as the primary space for a queer body to exist. Through this discussion I aim to activate debates both within and against the context of secular Islam on gendered political space and on those overlooked sexualized spaces in which the nation-state produces powerful yet unstable values to manage queer subjectivity in contemporary Turkey.
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
Türkiye'de Sosyal Medyanın Siyasi Katılıma Etkileri
(Uluslararası Kıbrıs Üniversitesi, 2015) Şener, Gülüm; Emre Öğün, Perrin; Akyıldız, Fatih
Sosyal ağların yaygınlaşmasıyla birlikte katılımcı demokrasi pratikleri artmakta, temsili demokrasilerin kısıtlı siyasi katılım biçimlerine alternatif yeni katılım biçimleri doğmakta, çevrimiçi siyasi pratikler ile çevrimdışı pratikler iç içe geçerek siyasi yaşamda önemli değişimlere neden olmaktadır. Önceki yıllarda Arap Baharı, Wall Streeti İşgal Et Hareketi, İspanyadaki ekonomik krize karşı ortaya çıkan Öfkeliler Hareketi vb. toplumsal hareketlerde sosyal medya haberleşme, örgütlenme ve eyleme geçme aşamalarında önemli, kalıcı siyasi ve toplumsal değişimlere yol açmıştır. Bir grup araştırmacı İnternetin siyasi olarak etkin ve siyasetle ilgili vatandaşları harekete geçirdiğini ileri sürmektedir. Diğer yandan şüpheci araştırmacılar, sosyal ağlar üzerinden erişim ve etkileşimin tek başına siyasi katılımı kapsamak için yeterli olmadığının, demokrasinin ilerlemesinde tek başına bir rol üstlenemeyeceğinin altını çizmektedir. Türkiyede Gezi Parkı Direnişi sürecinde sosyal medya, anaakım medyaya alternatif bir haber kaynağı olmuş, direnişçilerin haberleşmesinde, yardımlaşmasında ve örgütlenmesinde, direnişin sürekliliğinin sağlanmasında ve kitlelerin direnişe katılmalarında rol oynamıştır. Bir yanıyla, örgütsüzlerin, genç kuşağın, toplumda sınırlara itilen kimliklerin buluştuğu Gezi Parkı Direnişi, sosyal medya kullanımını da etkileyerek sosyal ağları direnişin mekânları haline getirmiş, yeni alternatif katılım ağlarının doğmasına vesile olmuştur. Gezi Direnişi hala anlaşılmaya çalışılırken, yurttaşların sosyal ağlardaki toplumsal ve siyasal katılımlarına dair ampirik verilerle genel bir durum değerlendirmesini ortaya koymak önem taşımaktadır. Bu çalışmanın amacı, Türkiye genelinde sosyal medyanın bireylerin siyasi katılımına etkilerini ölçümlemektir. Araştırmada veriler, 11 il bazında telefonla anket tekniğiyle toplanmıştır. Sonuç olarak sosyal medyanın bireylerin siyasi katılımına görece etkide bulunduğu, yaş, eğitim düzeyi, sosyo-ekonomik düzey ile bireylerin siyasete ilgi düzeyinin çevrim içi siyasete katılımda önemli faktörler olduğu ortaya çıkmıştır. With the proliferation of social networking sites, participatory democratic practices increase, new forms of political participation emerge as alternative to the limited ways of political participation in representative democracies, and also online and offline political practices merge, resulting in prominent changes in political life. In recent years, social media led some permanent political and social changes on communicational, organizational and action levels in social movements such as Arab Spring, Occupy Wall Street, Indignados which occurred against the economic crisis in Spain. A group of scholars argue that the Internet mobilizes people who are already politically active and interested in political issues. However, sceptic scholars underline that the access and interaction via social networking only is not adequate enough for political participation and also can not play a unique role for the enhancement of democracy. During Gezi Park Resistance in Turkey, social media became an alternative news source, it played an important role on communication, organization and cooperation of dissidents providing consistency of resistance by allowing the participation of masses. In a sense, Gezi Parkı Resistance, in which disorganized people, young generation, marginalized identities meet, has contributed to the emergence of new alternative participation networks and made the social media into the arena of the resistance by affecting also the use of social media. Whereas the efforts to understand and frame Gezi Movement still continue among scholars, it seems important to make a general assessment about the civic and political participation of citizens in social networks in the light of empirical findings. This study aims to determine the effects of social media on individuals political participation in Turkey at large. The data were gathered from 11 cities using phone survey method. One of the key findings of the study is that social media have a relative impact on individuals political participation; and variables such as age, education, socio-economic level and the level of interest for politics play an important role in online civic engagement
Citation - WoS: 9
Citation - Scopus: 12
Controlling the Growth of Particle Size and Size Distribution of Silica Nanoparticles by the Thin Film Structure
(Springer, 2012) Uysal, Bengü Özuğur; Tepehan, Fatma Zehra
Nanostructured silicondioxide thin films were prepared by sol-gel spin coating technique. The SiO2 films were made using a conventional mixture of tetraethoxysilane (TEOS) deionized water and ethanol with various NH3/TEOS ratios. The nanostructured silica films were made using a mixture of the SiO2 sol and regular SiO2 sol to control the enlargement of the particles inside the films. The structural morphological and optical characterizations of the as-deposited and annealed films were carried out using X-ray diffraction (XRD) atomic force microscopy scanning electron microscopy NKD spectrophotometer and ultraviolet-visible (UV-vis) spectroscopy. The transmittance data of the infrared spectra of the films were recorded using an FT-IR Spectrometer. The XRD studies showed that as-deposited films were amorphous and the formation of the alfa-cristobalite phase of the silica film was investigated at annealing temperature close to 1100 A degrees C. Optical properties of the transmittance spectra in the s and p-polarization modes were collected. Refractive indices and extinction coefficients were determined with respect to the NH3/TEOS ratios in the compositions of the films. Optical cut-off wavelength values were investigated from the extrapolation of the absorbance spectra which was estimated from the UV-vis spectroscopy measurements. A red shift in the absorption threshold indicated that the size of silica nanoparticles was increased by an increase in the NH3/TEOS volume ratio from 1:64 to 1:8.
Citation - WoS: 12
Citation - Scopus: 16
Social Media Adoption: a Process-Based Approach
(Taylor & Francis Inc, 2016) Toker, Ayşegül; Seraj, Mina; Kuşçu, Asli; Yavuz, Ramazan; Koch, Stefan; Bisson, Christophe
This research conceptualizes and measures social media adoption (SMA) of companies with a process-based approach and explains its antecedents of micro- and macro-environment size and ownership as well as its consequence of intention to increase resources dedicated to social media. Based on data from 310 Turkish small and medium enterprises the study first develops a conceptual framework on the pillars of internal and external stakeholder focus as well as relationship and information oriented implementation. Based on these two dimensions it discusses the novel concepts of social customer relations social stakeholder communication social intelligence and social responsiveness related to SMA. The study further indicates that ownership type and micro environment play a role in SMA and that path dependence exists in the interplay of current adoption and future intentions.
Citation - WoS: 1
Women and Turkish Cinema: Gender Politics Cultural Identity and Representation
(Routledge Journals Taylor & Francis Ltd, 2014) Akser, Murat
[Abstract Not Available]
Citation - WoS: 8
Citation - Scopus: 9
An Inverse Coefficient Problem for a Quasilinear Parabolic Equation With Periodic Boundary and Integral Overdetermination Condition
(Wiley-Blackwell, 2015) Bağlan, İrem Sakınç; Kanca, Fatma
In this paper the inverse problem of finding the time-dependent coefficient of heat capacity together with the solution periodic boundary and integral overdetermination conditions is considered. Under some natural regularity and consistency conditions on the input data the existence uniqueness and continuous dependence upon the data of the solution are shown. Some considerations on the numerical solution for this inverse problem are presented with an example. Copyright (c) 2014 John Wiley & Sons Ltd.
A Robust Localization Framework To Handle Noisy Measurements in Wireless Sensor Networks
(IEEE, 2009) Erten, Cesim; Karataş, Ömer
We construct a robust localization framework to handle noisy measurements in wireless sensor networks. Traditionally many approaches employ the distance information gathered from ranging devices of the sensor nodes to achieve localization. However the measurements of these devices may contain noise both as hardware noise and as environmental noise due to the employment conditions of the network. It Is necessary to provide a general framework that handles such a noise in data and yet still be applicable within several localization algorithms. In order to handle noise in distance measurements our framework utilizes convex constraints and confidence intervals of a random variable. At the end of the localization process nodes are assigned to a set of feasible regions with corresponding probabilities. The accuracy of the localization can be adjusted and the framework can easily be embedded to work within previously suggested localization algorithms.
Citation - WoS: 7
Citation - Scopus: 8
Novel Mutants of the Aubergine Gene
(Taylor & Francis Inc, 2016) Şahin, H. Bahar; Karataş, Ömer Faruk; Specchia, Valeria; Di Tommaso, Silvia D.; Diebold, Celine; Bozzetti, Maria Pia; Giangrande, Angela
Aubergine is an RNA-binding protein of the Piwi clade functioning in germline in the piRNA pathway that silences transposons and repetitive sequences. Several mutations of this gene exist but they mostly result in truncated proteins or correspond to mutations that also affect neighboring genes. We have generated complete aubergine knock-out mutants that do not disrupt the neighboring genes. These novel mutants are characterized by PCR and sequencing. Their nature is confirmed by female sterility and by the presence of crystals in testes common to the aubergine loss of function mutations. These mutants provide novel and more appropriate tools for the study of the piRNA pathway that controls genome stability.
Citation - WoS: 38
Does Firm Age Affect Profitability? Evidence From Turkey
(Int Inst Social & Economics Sciences-IISES, 2016) Akben Selçuk, Elif
The objective of this study is to investigate the impact of firm age on the profitability of Turkish firms listed on Borsa Istanbul. Using a dataset covering the years between 2005 and 2014 and consisting of 302 non-financial firms per year on the average a fixed effects model with robust standard errors is estimated. Results reveal that there is a negative and convex relationship between firm age and profitability measured by return on assets return on equity or gross profit margin. This suggests that younger firms start to see a decline in their profitability from the beginning but they may become profitable again at an old age. Implications are provided.
Citation - WoS: 3
Modeling of Visible Light Channels and Performance Analysis of Aco-Ofdm
(IEEE, 2015) Yeşilkaya, Anıl; Alsan, Hüseyin Fuat; Miramirkhani, Farshad; Panayırcı, Erdal; Şenol, Habib; Uysal, Murat
Spectrum scarcity of traditional radio communication has led communication engineers to find new alternatives. Indoor visible light communication is one alternative to solve this problem since its spectrum is not regulated and it has much wider bandwidth then traditional communication systems. This increased the research done in the field of visible light communications. However a proper indoor channel model is lacking and all previous studies assumes that only additive white Gaussian noise (AWGN) is present. Lack of proper channel model has motivated us to model a realistic indoor visible light channel. After modeling the indoor visible light channel the performance of an asymmetrically clipped optical OFDM (ACO-OFDM) system which is suitable for optical communications is investigated and compared to that of the AWGN optical channels.
Citation - Scopus: 63
Optical Ofdm With Index Modulation for Visible Light Communications
(Institute of Electrical and Electronics Engineers Inc., 2015) Basar, Ertugrul; Panayırcı, Erdal
In this paper we propose optical orthogonal frequency division multiplexing with index modulation (O-OFDM-IM) for visible light communications (VLC) systems employing light emitting diodes (LEDs) and photodetectors (PDs). The proposed scheme uses the indices of the active subcarriers of an optical OFDM system to transmit additional information bits. In the proposed scheme the bipolar signals are asymmetrically clipped or DC biased and a log-likelihood ratio (LLR) calculation based detector is used to determine the indices of the active subcarriers. Our computer simulations show that the O-OFDM-IM achieves better error peformance compared to classical optical OFDM schemes. © 2015 IEEE.
Citation - WoS: 57
Citation - Scopus: 73
Drug Design for Cns Diseases: Polypharmacological Profiling of Compounds Using Cheminformatic, 3d-Qsar and Virtual Screening Methodologies
(Frontiers Media Sa, 2016) Nikolic, Katarina; Mavridis, Lazaros; Djikic, Teodora; Vucicevic, Jelica; Agbaba, Danica; Yelekçi, Kemal; Mitchell, John B. O.
The diverse cerebral mechanisms implicated in Central Nervous System (CNS) diseases together with the heterogeneous and overlapping nature of phenotypes indicated that multitarget strategies may be appropriate for the improved treatment of complex brain diseases. Understanding how the neurotransmitter systems interact is also important in optimizing therapeutic strategies. Pharmacological intervention on one target will often influence another one, such as the well-established serotonin-dopamine interaction or the dopamine-glutamate interaction. It is now accepted that drug action can involve plural targets and that polypharmacological interaction with multiple targets, to address disease in more subtle and effective ways, is a key concept for development of novel drug candidates against complex CNS diseases. A multi-target therapeutic strategy for Alzheimer's disease resulted in the development of very effective Multi-Target Designed Ligands (MTDL) that act on both the cholinergic and monoaminergic systems, and also retard the progression of neurodegeneration by inhibiting amyloid aggregation. Many compounds already in databases have been investigated as ligands for multiple targets in drug discovery programs. A probabilistic method, the ParzenRosenblatt Window approach, was used to build a "predictor" model using data collected from the ChEMBL database. The model can be used to predict both the primary pharmaceutical target and off-targets of a compound based on its structure. Several multi-target ligands were selected for further study, as compounds with possible additional beneficial pharmacological activities. Based on all these findings, it is concluded that multipotent ligands targeting AChE/MAO-A/MAO-B and also D-1-R/D-2-R/5-HT2A-R/H-3-R are promising novel drug candidates with improved efficacy and beneficial neuroleptic and procognitive activities in treatment of Alzheimer's and related neurodegenerative diseases. Structural information for drug targets permits docking and virtual screening and exploration of the molecular determinants of binding, hence facilitating the design of multi-targeted drugs. The crystal structures and models of enzymes of the monoaminergic and cholinergic systems have been used to investigate the structural origins of target selectivity and to identify molecular determinants, in order to design MTDLs.
Citation - WoS: 12
Citation - Scopus: 15
Improving Opencl Programmability With the Heterogeneous Programming Library
(Elsevier Science Bv, 2015) Vinas, Moises; Fraguela, Basilio B.; Bozkuş, Zeki; Andrade, Diego
The use of heterogeneous devices is becoming increasingly widespread. Their main drawback is their low programmability due to the large amount of details that must be handled. Another important problem is the reduced code portability as most of the tools to program them are vendor or device-specific. The exception to this observation is OpenCL which largely suffers from the reduced programmability problem mentioned particularly in the host side. The Heterogeneous Programming Library (HPL) is a recent proposal to improve this situation as it couples portability with good programmability. While the HPL kernels must be written in a language embedded in C++ users may prefer to use OpenCL kernels for several reasons such as their growing availability or a faster development from existing codes. In this paper we extend HPL to support the execution of native OpenCL kernels and we evaluate the resulting solution in terms of performance and programmability achieving very good results.
Citation - WoS: 9
Citation - Scopus: 9
Information Cascades, Short-Selling Constraints, and Herding in Equity Markets
(Borsa İstanbul Anonim Şirketi, 2020) Tiniç, Murat; Iqbal, Muhammad Sabeeh; Mahmud, Syed F.
This paper examines the relationship between informed trading and herding in Borsa İstanbul. Our firm-level cross-sectional analysis asserts that informed trading can significantly increase future herding levels. Furthermore, we show that the relationship between informed trading and herding intensifies under short-selling restrictions. Our results confirm the predictions of the informational cascades framework where the individuals disregard their private information to follow others. We show that information cascades are relevant both for buy-side herding and sell-side herding. Short-selling restrictions may reinforce the herding behaviour since informed investors may not be able to clear out potential price misalignments.
Ecological Strategies for Designing Halys River: a Landscape of Flux
(Scibulcom Ltd, 2019) Yıldırım-Okta, Birge
Natural and manmade disasters led to the emergence of new approaches in designing our environment in the postindustrial era. Modern technological infrastructures failure to respond to the challenges from environmental hazards led the designers to restructure the landscape. This in turn, led to a shift in landscape architecture, planning and architecture discipline. In the past decade green infrastructure has been a topic for debate among practitioners and theorists across different disciplines, ranging from architecture, urban planning, engineering to geography and biology. The discourse appears to be an operational and promising tool in planning, designing resilient eco-system based infrastructures. This paper discusses an interdisciplinary design proposal for Sivas, Halys River in a landscape urbanistic manner. The aim of the project was to create a cultural and ecological corridor in Sivas, Turkey that is adaptable to changes and dynamics over time, considerate to ecosystem and human conditions. In the light of discourse of green infrastructure the paper derives adaptive design strategies for ecological urbanism.

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