105 results on '"Yiğit, Fatih"'
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2. Effects of high-intensity laser therapy on pain, functional status, hand grip strength, and median nerve cross-sectional area by ultrasonography in patients with carpal tunnel syndrome
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Yiğit, Fatih and Ordahan, Banu
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- 2023
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3. Classification of XTEKS Companies During COVID-19 Pandemic using Fuzzy-Analytic Hierarchy Process and Fuzzy-C-Means
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Yiğit, Fatih, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Kahraman, Cengiz, editor, Sari, Irem Ucal, editor, Oztaysi, Basar, editor, Cebi, Selcuk, editor, Cevik Onar, Sezi, editor, and Tolga, A. Çağrı, editor
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- 2023
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4. A three-stage fuzzy neutrosophic decision support system for human resources decisions in organizations
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Yiğit, Fatih
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- 2023
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5. A Proposed Methodology for Risk Classification Using Fuzzy Group Decision Making and Fuzzy C-Means
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Yiğit, Fatih, Dönmez, İlknur, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Kahraman, Cengiz, editor, Tolga, A. Cagri, editor, Cevik Onar, Sezi, editor, Cebi, Selcuk, editor, Oztaysi, Basar, editor, and Sari, Irem Ucal, editor
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- 2022
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6. Efficacy of inhaled iloprost in children with pulmonary hypertension after pediatric cardiac surgery: a case series
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Arslanoğlu, Ergin, primary, Bakhshaliyev, Shiraslan, additional, Kara, Kenan Abdurrahman, additional, Yiğit, Fatih, additional, Yeşiltaş, Mehmet Ali, additional, Huseynzade, Shabnam, additional, Özalp, Zeynep Gülben Kük, additional, and Karaci, Ali Rıza, additional
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- 2024
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7. The Driving Force of Market Value and Financial Performance in Knowledge-Based Business Environment: Intellectual Capital
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Yigit, Fatih, Dincer, Hasan, editor, and Yüksel, Serhat, editor
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- 2021
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8. The importance and prognostic effect of thyroid hormones in patients with transposition of the great arteries.
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Arslanoğlu, Ergin, Kara, Kenan Abdurrahman, Bakhshaliyev, Shiraslan, Yiğit, Fatih, Tanrıverdi, Doğan Çağrı, Tunçer, Eylem, Çine, Nihat, and Ceyran, Hakan
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THYROID hormones ,TRANSPOSITION of great vessels ,CONGENITAL heart disease ,THYROID gland function tests ,CONGENITAL hypothyroidism - Abstract
Objectives: Transposition of the great arteries (TGA) is a rare congenital heart disease that occurs in 3 in 10,000 newborns and is rapidly fatal (90%) within one year if left untreated. The prognosis of this pathology changed after introducing an early arterial switch operation (ASO), while the left ventricle could still adapt to systemic high-pressure conditions. Appropriate regulation of thyroid hormones positively impacts metabolism, cardiac function, and postoperative recovery. Therefore, regular thyroid hormone monitoring and thyroid function monitoring of TGA patients may help to improve the health status and prognosis of this group of postoperative patients. Methods: In our study, 127 patients who underwent ASO at our pediatric cardiac surgery clinic between 01.01.2014 and 18.09.2021 were retrospectively analyzed and included. Among the patients, 43% (n=54) were females, and 57% (n=73) were males. Results: The coronary arteries were normal in 89.7% (n=114) and abnormal in 10.3% (n=13) of the patients. Twenty-one of the patients exited, and mortality was calculated to be 16.5%. There were no significant differences in mortality or thyroid stimulating hormone (TSH), free thyroxine (T4), or free triiodothyronine (T3) values (P=0.674, P=0.345, P=0.478). In our study, in which we investigated the effect of thyroid hormone levels on prognosis in neonatal patients with TGA with normal free T3, T4, and TSH values, we found that TSH levels were greater in the group with advanced aortic regurgitation and exitus, although the effect of thyroid hormones on postoperative results was not statistically significant. Conclusions: Congenital hypothyroidism is a common disease with cardiac effects. During the neonatal period, this disease may conceal itself. Careful, expert clinical follow-up and clinical trials are crucial to improve outcomes in the surgical treatment of transposition of the great arteries, a complex congenital heart disease. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Bir Ev İçin Faz Değişim Malzemesi ile Güneş Isısı Kazancının Değerlendirilmesi
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YİĞİT, Fatih, primary
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- 2024
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10. Multi-Objective Optimization of Reliable Remanufacturing Problem with M/M/M/K Queues
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Hajipour, Vahid, primary, Hadad Kaveh, Sharmineh, additional, and Yiğit, Fatih, additional
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- 2024
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11. The Role of Market Risk in Innovative Working Behaviour of Companies: A Comparative Analysis Between Turkey and Mexico Using Multivariate GARCH Methodology
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Yiğit, Fatih, Atgür, Musa, Dincer, Hasan, editor, and Yüksel, Serhat, editor
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- 2020
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12. A new Fuzzy C-Means and AHP-based three-phased approach for multiple criteria ABC inventory classification
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Yiğit, Fatih and Esnaf, Şakir
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- 2021
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13. Congenital cardiac surgery and diaphragmatic paralysis: efficacy of diaphragm plication.
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Arslanoğlu, Ergin, Bakhshaliyev, Shiraslan, Kara, Kenan Abdurrahman, Yiğit, Fatih, Yeşiltaş, Mehmet Ali, Altunyuva, Kaan, Özalp, Zeynep Gülben Kük, and Karaci, Ali Rıza
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CARDIAC surgery ,PHRENIC nerve ,DIAPHRAGM (Anatomy) ,PARALYSIS ,CHILD patients ,CARDIOPULMONARY bypass ,ARTIFICIAL respiration ,FACIAL paralysis - Abstract
Background: Diaphragmatic paralysis due to phrenic nerve injury is a rare but potentially serious complication following congenital cardiac surgery, with reported incidences ranging from 0.28 to 5.6%. Early plication has been recommended for children diagnosed with diaphragmatic paralysis, especially those requiring prolonged respiratory support after cardiopulmonary bypass. It is important to note that late plication may jeopardize the results of successful surgical plication due to diaphragm atrophy. Results: This retrospective study was performed between May 2020 and June 2023. Patients who could not be weaned from the ventilator and underwent diaphragmatic plication in symptomatic patients after phrenic nerve injury were included in the study. During the study period, 22 (3.5%) of 624 pediatric patients operated for congenital heart disease required diaphragm plication. The mean age of the patients ranged from 1 month to 13 years with a mean of 23.88 ± 37.99 months. Fourteen (63.6%) of the patients were female, and 8 (36.4%) were male. Two of the patients (9%) were exited due to ventilator-associated pneumonia and sepsis. Conclusions: In conclusion, diaphragmatic paralysis after congenital heart surgery is a rare but important complication that can lead to serious respiratory and cardiac problems. Diaphragmatic plication has been shown to be an effective intervention for pediatric patients with the potential to improve pulmonary function, reduce dyspnea, and minimize complications associated with diaphragmatic paralysis. Careful consideration of patient selection, timing, and potential complications is crucial in optimizing the outcomes of this surgical intervention. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Hybrid Approach for the Financial Assessment of Companies using Fuzzy Multi-Criteria Decision-Making and Self-Organizing Maps.
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YİĞİT, Fatih
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ANALYTIC hierarchy process ,FINANCIAL ratios ,SELF-organizing maps ,LITERATURE reviews ,FINANCIAL statements ,MULTIPLE criteria decision making - Abstract
Copyright of Itobiad: Journal of the Human & Social Science Researches / İnsan ve Toplum Bilimleri Araştırmaları Dergisi is the property of Itobiad: Journal of the Human & Social Science Researches and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2024
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15. Neurological complications after pediatric cardiac surgery
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Arslanoğlu, Ergin, Kara, Kenan Abdurrahman, Yiğit, Fatih, Arkan, Cüneyt, Uslu, Ufuk, Şavluk, Ömer Faruk, Yılmaz, Abdullah Arif, Tunçer, Eylem, Çine, Nihat, and Ceyran, Hakan
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- 2021
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16. Bankruptcy: An Examination of Different Approaches
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Yigit, Fatih, Dincer, Hasan, editor, Hacioglu, Ümit, editor, and Yüksel, Serhat, editor
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- 2018
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17. Factors affecting leverage during a financial crisis: Evidence from Turkey
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Jermias, Johnny and Yigit, Fatih
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- 2019
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18. A Three-Stage Fuzzy Neutrosophic Sets-Based Methodology for Training Assignment
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Yiğit, Fatih, primary
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- 2023
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19. Macroeconomic Facts for Telecom Industry in MINT Countries
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Coban, Ayse, Yigit, Fatih, Kalkavan, Hakan, Kizil, Cevdet, and Seker, Sadi Evren
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- 2016
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20. When Should the Sternum Be Closed After Aortic Surgery?
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Başar, Veysel, primary, Yiğit, Fatih, additional, Jafarov, Fariz, additional, and Sunar, Hasan, additional
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- 2022
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21. A SWARA-VAHP and FCM Based Model Proposal for MCIC (extended abstract)
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Yiğit, Fatih and Atay, Metehan
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Stepwise Weight Assessment Ratio Analysis (SWARA) ,ABC Analysis ,Multi-Criteria Inventory Classification ,Fuzzy C-Means (FCM) Algorithm ,Analytical Hierarchy Process (AHP) - Abstract
ABC analysis is an efficient and easy-to-use methodology to classify inventory based on a single or multi-criteria basis that may consist of thousands of items. The evolution of the subject is now focused on multiple criteria instead of a single criteria. The proposed approach to the multi-criteria inventory classification (MCIC) problem integrates improved version of Stepwise Weight Assessment Ratio Analysis and Voting Analytic Hierarch Process (SWARA-VAHP) and Fuzzy-C-Means. This new approach is called AHP-SWARA-FCM-RVeto and proposed in this study for the first time. The proposed model integrates SWARA-VAHP which is an improved version of AHP. By using SWARA-VAHP, minimum information from experts will be sufficient. Also incorporating FCM will allow users to make clustering based on figures but also gives the flexibility to assign members between different clusters by using membership values. A real life example is used to show the application of the proposed model. In the real-life example, the main advantage of compliance with the Pareto principle of the proposed method is shown.
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- 2022
22. Seçilmiş Makroekonomik Değişkenlerin Bist100 Endeksi Üzerindeki Asimetrik Etkileri
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CANÖZ, İsmail, primary and YİĞİT, Fatih, additional
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- 2022
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23. The Relationship Between Volatility and Sovereign Credit Risk in the Emerging Markets: A Nonlinear ARDL Approach
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YİĞİT, Fatih, primary and ALİYEV, Fuzuli, additional
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- 2022
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24. Prophylactic Use of Levosimendan in High-Risk Coronary Artery Disease: Retrospective Clinical Research
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BAŞAR, Veysel, primary, ÖZTÜRK, Fatih, additional, YİĞİT, Fatih, additional, ZENGİN, Ahmet, additional, ÇİÇEKÇİOĞLU, Ferit, additional, HANÇER, Hakan, additional, FEDAKAR, Ali, additional, and YANARTAŞ, Mehmed, additional
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- 2022
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25. A Poisson-Regression, Support Vector Machine and Grey Prediction Based Combined Forecasting Model Proposal: A Case Study in Distribution Business
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YİĞİT, Fatih, primary, ESNAF, Şakir, additional, and YALÇIN KAVUŞ, Bahar, additional
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- 2021
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26. IMPROVEMENT OF SUSTAINABLE DEVELOPMENT AND GREEN FINANCE STUDIES
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YİĞİT, Fatih and CANÖZ, İsmail
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Sustainable development,green finance,environmental protection ,Economics ,Sürdürülebilir kalkınma,yeşil finansman,çevresel koruma ,устойчивое развитие,зеленое финансирование,охрана окружающей среды ,İktisat - Abstract
То, что разрушение окружающей среды, возникшее с началом промышленной революции, несет угрозу в будущем, заставляет правительства беспокоиться. Поэтому они приняли решение поддерживать экологически чувствительные проекты, чтобы устранить разрушения и обеспечить пригодный для жизни мир. Для обеспечения устойчивого развития почти в каждом секторе была разработана экологическая основа. Параллельно с этим произошли изменения в финансовом секторе, объединенные под названием «зеленое финансирование». Целью данного исследования является повышение осведомленности о зеленом финансировании и представление политики продвижения зеленого финансирования в Турции. В этой связи обсуждаются взгляды, выработанные в академическом мире в отношении концепций устойчивого развития и зеленого финансирования, и упоминаются результаты текущих исследований, отраженные в литературе. Включены предложения относительно шагов по расширению зеленого финансирования и политики, которым необходимо следовать., The point that the environmental destruction that emerged with the beginning of the industrial revolution will bring the world in the future causes the governments to worry. Therefore, they have adopted to support environmentally sensitive projects to eliminate the destruction and provide a livable world. To ensure sustainable development, an environment-friendly framework has been developed in almost every sector. Parallel to this, there has been a change and development in the finance sector, and all of these have been gathered under the title of green finance. This study aims to raise awareness of green finance and present policies for promoting green finance in Turkey by presenting a framework of studies on the subject. In this regard, the perspectives produced in the academic world on the concepts of sustainable development and green finance are discussed, and the findings of current studies in the literature are mentioned. Suggestions regarding the steps to expand green finance are concerned, and policies to be followed are included., Sanayi devriminin başlangıcı ile birlikte hissedilir derecede ortaya çıkan çevresel tahribatın ileride dünyayı getireceği nokta hükümetleri endişeye sevk etmektedir. Tahribatın giderilmesi ve yaşanabilir bir dünyanın sağlanması için çevreye duyarlı projelerin desteklenmesi benimsenmiştir. Sürdürülebilir kalkınmanın sağlanabilmesi için hemen hemen her sektörde çevreye duyarlı bir çerçeve geliştirilmiştir. Buna paralel olarak, finans sektöründe de bir değişim ve gelişim yaşanmıştır ve bunların tümü yeşil finansman başlığı altında toplanmıştır. Bu çalışmanın amacı, yeşil finansman konusunun farkındalığını artırmak ve konuyla ilgili çalışmaların bir çerçevesini sunarak Türkiye’de yeşil finansmanın teşviki için politikalar sunmaktır. Bu hususta, sürdürülebilir kalkınma ve yeşil finansman kavramlarına karşı akademik dünyada üretilen bakış açıları ele alınarak, literatürde yer alan güncel çalışmaların bulgularına değinilmiştir. Yeşil finansmanın yaygınlaştırılabilmesi için atılması gereken adımlara ilişkin öneriler tartışılmış ve takip edilmesi gereken politikalara yer verilmiştir.
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- 2021
27. The Role Of Shunt In The Norwood Procedure
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Çine, Nihat, primary, Yiğit, Fatih, additional, Arslanoğlu, Ergin, additional, and Ceyran, Hakan, additional
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- 2021
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28. Scimittar Syndrome; Right time to operate? and mid-term results.
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Kara, Kenan Abdurrahman, primary, Arslanoğlu, Ergi̇n, additional, Tomrukçu, Fatih, additional, Yılmaz, Abdullah Arif, additional, Yiğit, Fatih, additional, and Ceyran, Hakan, additional
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- 2021
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29. Disease oriented ECMO results; specific considerations for different pathologies
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Arslanoğlu, Ergi̇n, primary, Kara, Kenan Abdurrahman, additional, Yiğit, Fatih, additional, Özbek, Babürhan, additional, Yavuz, Yasemin, additional, Ukil Işıldak, Fatma, additional, Tunçer, Eylem, additional, Çine, Nihat, additional, and Ceyran, Hakan, additional
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- 2021
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30. How does the Intellectual Capital Affect the Firm Performance? Current Evidence from Developing Countries
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YİĞİT, Fatih
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Social ,Sosyal ,Intellectual Capital,Firm Performance,Fragile Five,VAIC ,Entelektüel Sermaye,Firma Performansı,Kırılgan Beşli,EKDK - Abstract
Bu çalışma, Brezilya, Hindistan, Endonezya, Güney Afrika ve Türkiye'den 2.619 halka açık imalat firmasının verilerini kullanarak 2010-2020 döneminde entelektüel sermaye ile firma performansı arasındaki ilişkiyi incelemektedir. Çalışmanın literatüre ilk katkısı, gelişmiş ülkelere ait veriler yerine, gelişmekte olan ülkeler arasında en hassas ekonomiler olan “kırılgan beşli” ülkelerinin verilerinin kullanılmasıdır. İkinci olarak, entelektüel sermaye yoğun oldukları sezgisel olarak anlaşılabilecek bankacılık, teknoloji ve hizmetler gibi sektörler yerine fiziksel ve finansal sermaye yoğun olarak bilinen imalat sektörü firmaları incelenmektedir. Son olarak ise verinin özelliğine en uygun ekonometrik yöntem tespit edilerek uygulanmaktadır. Çalışmanın bulguları, kullanılan sermaye etkinliğinin, tüm ülkelerde firma performansı üzerinde pozitif bir etkiye sahip olduğunu göstermektedir. Entelektüel sermayenin önemli bir bileşeni olan beşeri sermaye etkinliğine ilişkin sonuçlar, gelişmekte olan ülkelerde beşeri sermayenin halen önemsenmediğini ve beşeri sermayeye gerekli yatırım yapılmadığından firma performansı üzerindeki etkisinin gözlemlenemediğini işaret etmektedir. Entelektüel sermayenin yapısal sermaye bileşeninin ise gelişmekte olan ülkelerde farkına varılan ve yatırım yapılan bir unsur olduğu gözlemlenmektedir., This study investigates the relationship between intellectual capital and firm performance in the period of 2010-2020 using the data of 2.619 listed manufacturing firms from Brasil, India, Indonesia, South Africa, and Turkey. The first contribution of the study to the literature is the use of data from “fragile five” countries, which are the most delicate economies among developing countries, rather than the data from developed countries. Secondly, instead of sectors such as banking, technology, and services, which can be understood intuitively as being intellectual capital intensive, the manufacturing sector firms, which are known as physical and financial capital intensive, are examined. Finally, the most appropriate econometric method for the characteristics of the data is determined and applied. The findings of the study show that the capital employed efficiency has a positive effect on firm performance in all countries. The results regarding human capital efficiency, which is an important component of intellectual capital, point out that human capital is still underestimated in developing countries, and its effect on firm performance cannot be observed due to the lack of necessary investment in human capital. It is observed that the structural capital component of intellectual capital is an element that has been recognized and invested in developing countries.
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- 2021
31. Effects of patient blood management in pediatric heart surgery.
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Arslanoğlu, Ergin, Kara, Kenan A., Işık, Mehmet E., Yiğit, Fatih, Uslu, Ufuk, Tunçer, Eylem, Çine, Nihat, and Ceyran, Hakan
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CARDIAC surgery ,BLOOD transfusion reaction ,BLOOD products ,HEMATOCRIT ,PEDIATRIC cardiology - Abstract
Copyright of Cirugía y Cirujanos is the property of Publicidad Permanyer SLU and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2022
- Full Text
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32. TÜRK AVROVİLLERİNİN PİYASA DEĞERİNİ ETKİLEYEN ÜLKEYE ÖZGÜ DEĞİŞKENLERİN BELİRLENMESİ: NARDL YAKLAŞIMI
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YİĞİT, Fatih, primary and CANÖZ, İsmail, additional
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- 2021
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33. Prenatal Genetik Tanı Testleri Hakkında Türkiye'deki Üniversite Öğrencilerinin Bilinç Düzeyinin Araştırılması.
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Coşkunpınar, Ender, Şişman, Aslı, Akgöl, Hilal, Kaya, Mustafa, and Yiğit, Fatih Emre
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Copyright of Hamidiye Medical Journal is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
34. Atorvastatin tayini için yeni bir spektrofotometrik yöntem
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Yiğit, Fatih, Aydın, Işıl, Dicle Üniversitesi, Sağlık Bilimleri Enstitüsü, Analitik Kimya Anabilim Dalı, Yiğit, Fatih, and Analitik Kimya Anabilim Dalı
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Farmasötik formülasyon ,Formularies ,UV-VIS ,Pharmaceutical formulation ,UVVIS ,Pharmacy and Pharmacology ,Spectrophotometry ,Ultraviolet rays ,Yük transfer kompleksi ,Atorvastatin ,Anticholesteremic agents ,Eczacılık ve Farmakoloji ,Charge transfer complex ,Quinalizarin - Abstract
Lisansüstü tezlerin elektronik ortamda toplanması, düzenlenmesi ve erişime açılması konusuna ilişkin yök'ün 18.06.2018 tarihli yönergesine istinaden artık bu tarihten sonra gizlilik şartı aranmayan bütün tezler erişime açılacaktır. Amaç: Farmasötik formülasyon ve ilaçlarda bulunan Atorvastatin'in miktarsal olarak tayini için reaktif olarak quinalizarin yardımıyla yük transfer kompleksi oluşturarak ekstraksiyona gerek kalmaksızın spektrofotometrik yöntem geliştirilmesi amaçlanmıştır. Gereç ve Yöntem: Atorvastatin ve reaktif olarak kullanılan Quinalizarin ile metanol ortamında oda şartlarında 573 nm dalgaboyunda maksimum absorbans veren mavi renkli yük transfer kompleksi oluşturulmuştur. Reaksiyonu etkileyecek farklı değişkenler optimize edilmiş ve çalışılmıştır. Bulgular: Atorvastatin'in kantitatif tayininde; oluşturulan yük transfer kompleksinin çok yoğun bir renk vermesi, maksimum renk gelişiminin sağlanması için ve en uygun koşulları oluşturmak için denemeler yapılmıştır. Yöntemin geliştirilmesi ve incelenmesi için; çözücü yapısı etkisinin değerlendirilmesi, reaktif konsantrasyonunun etkisinin araştırılması ve reaksiyonu tamamlamak için gereken sürenin belirlenmesi ve reaksiyonun stokiyometrisinin değerlendirilmesi gibi süreçler takip edildi. Sonuç: Önerilen yöntem aynı zamanda; sadece bir çözücü içindeki, atorvastatin ile quinalizarin arasındaki yük transfer reaksiyonu olma avantajına sahiptir ve aynı zamanda geliştirilebilir olma özelliği vardır. Linearitesi, 10-100 µg/mL aralığında kalibrasyon doğrusu elde edilmiş, tespit ve nicelendirme sınırları, sırasıyla 1,49 g/mL ve 4,98 g/mL olarak hesaplanmıştır. Bu nedenle, önerilen yük transfer kompleksi reaksiyonu, kalite kontrol laboratuarlarında atorvastatinin rutin analizlerinde pratik ve ekonomiktir Aim: In order to determine the amount of atorvastatin found in pharmaceutical formulations and drugs, it is aimed to develop a spectrophotometric method without the need for extraction by forming a charge transfer complex with the help of quinalizarin as a reagent. Material and Method: A blue-colored charge transfer complex with maximal absorbance at 573 nm was generated in the room environment in the presence of kinetics with methanol. Different variables that affect the reaction have been optimized and studied. Results: In quantitative determination of atorvastatin; Experiments were conducted to provide the most favorable conditions to ensure a very dense color and maximum color development of the generated charge transfer complex. For the development and analysis of the method; The process of evaluating the effect of the solvent structure, studying the effect of the reagent concentration and evaluating the time required to complete the reaction and the stoichiometry of the reaction were followed. Conclusion: The proposed method is also; it has the advantage of being the charge transfer reaction between atorvastatin and quinalizarin in a solvent only and can be improved. The linearity of the calibration line was obtained between 10-100 g / mL, and the detection and quantification limits were calculated as 1,49 µg/mL and 4,98 µg/mL, respectively. Therefore, the proposed charge transfer complex reaction is practical and economical in routine analysis of atorvastatin in quality control laboratories. Abdi İbrahim İlaç San.ve Tic.A.Ş.
- Published
- 2019
35. Proposal of a decision making methodology for inventory management using particle swarm optimization and grey forecasting
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Yiğit, Fatih, Esnaf, Şakir, Endüstri Mühendisliği Anabilim Dalı, İÜC, Lisansüstü Eğitim Enstitüsü, Endüstri Mühendisliği Ana Bilim Dalı, and Yiğit, Fatih
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Endüstri ve Endüstri Mühendisliği ,Neuro fuzzy logic ,Sinirsel bulanık mantık ,Industrial and Industrial Engineering - Abstract
YÖK Tez No: 586015 Bu çalışmada stok yönetimi ve sipariş miktarlarının planlanması için bir karar verme metodolojisi önerilmiştir. Önerilen metodolojinin ilk aşamasında, Lolli ve diğerleri, (2014) tarafından yapılan çalışmada önerilen AHP-K ve AHP-K-Veto yönteminin tez kapsamında geliştirilip önerilen AHP-BCO-RVeto metodu ile ABC analizi yapılmıştır. Literatürde, Çok Kısıtlı Stok Sınıflaması problemlerinde kullanılan Analitik Hiyerarşi Prosesi(AHP) yöntemini kullanan, AHP-K ve AHP-K-Veto metotlarının sınıf sayılarını göz önüne almama başta olmak üzere eksik yanları önerilen metodoloji sayesinde geliştirilmiştir. Bu metodoloji Bulanık-C-Ortalamalar(BCO) kullanımı sebebiyle AHP-BCO-RVeto metodu olarak adlandırılmıştır. AHP-BCO-RVeto sınıflama sonuçlarının diğer metotlara olan performans karşılaştırmaları yapılmış ve daha iyi performans gösterdiği kanıtlanmıştır. Sınıflama aşamasının ardından gri tahminlemeyi (GT) de kullanan karma bir tahminleme yöntemi ile ileriye yönelik veriler tahmin edilmiştir. Söz konusu karma tahminleme sisteminde, poisson regresyon (PR) ve destek vektör makinaları (DVM) ile GT birlikte kullanılmıştır. Üç tahmin yönteminin kullanılması sayesinde, her yöntemin ayrı ayrı kullanılmasına oranla daha iyi sonuçlar verdiği kanıtlanmıştır. Öte yandan, GT'nin önemli bir avantajı olan az sayıdaki veriden tahmin gerçekleştirme sayesinde, az sayıdaki veri ile tahminler gerçekleştirmek mümkün olmuştur. Elde edilen bu tahminler son aşamada parçacık sürü algoritması kullanılarak yakın optimum sipariş miktarları tespit edilmesi için kullanılmıştır. Bu verilerin göz önüne alındığı noktada birim maliyet ve benzeri maliyet kalemlerinin en etkin şekilde tahmin edilmesi ve dolayısıyla ileriye yönelik alınan kararların en etkin olarak verilmesi amaçlanmıştır. Son aşamada, bu çalışmada önerilen karar metodolojisi ticari ürün satışı yapan bir şirketten alınan verilerle oluşturulan gerçek bir uygulamada kullanılmış ve mevcut duruma göre avantajları özetlenmiştir. In this study, the goal is to propose a new decision making methodology is proposed for inventory management and order quantity planning. In the first phase of the proposed methodology, a revised version of the AHP-K-Veto (Lolli et al., 2014) is used for the ABC analysis. In the literature, AHP-K-Veto method is used for the classificication for the area of Multiple Criteria Inventory Classification (MCIC) is improved mainly in the areas such as neglecting class sizes. So an improved version named AHP-BCO-RVeto which used Fuzzy-C-Means for classification is proposed in the thesis. Newly proposed algorithm named ABC-BCO-RVeto is shown to perform better compared to other alternative algorithms. In the second phase of proposed methodology the goal is to make the decisions in the most efficient way, datas such as demand and unit price are predicted. Grey forecasting, poisson regression and support vector machines are used in a hybrid method to make a reliable prediction. The performance is evelauated and showed superior performance by using these three metohds in a hybrid-merhod compared to sole methods used for prediction. Thanks to the the best advantage of the grey prediction is the ability to be used with very few datas which prevents any problems when very low datas are available, such perdiction became available with very few datas. The predicted values are used to determine the optimum values to maximise the profit by using Particle Swarm Optimization(PSO) Algoritms. The phase aims to have the most accurate predictions so that decision for the upcoming periods is performed in the most efficient way possible. In the last phase, data from a company that sells commercial products are solved with the proposed methodology and its advantages with the current status are given.
- Published
- 2019
36. HİSSE SENEDİ PİYASALARI ARASINDA OYNAKLIK YAYILIMI ETKİSİ ÜZERİNE BİR İNCELEME: ÇİN, RUSYA VE TÜRKİYE ÖRNEĞİ
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YİĞİT, Fatih and ATGÜR, Musa
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Business Finance ,Hisse Senedi Piyasaları,Oynaklık Yayılımı,DCC-MGARCH ,İşletme Finans ,Stock Markets,Volatility Spillover,DCC-MGARCH - Abstract
Today, with the liberalization of international capital flows, the free orientation of savings and funds to the capital markets that will generate the highest return has made different financial markets interactive. After the most recent 2008 global financial crisis, fluctuations in stock markets brought discussions on the international finance structure. This study examines the volatility spillover from China and Russia stock markets to Turkish stock market. In this context, the period between January 1, 2009 and August 9, 2017 is examined with daily data, and the dynamic conditional correlation multivariate GARCH (DCC-MGARCH) model is applied. Stock market price index data of all three countries (BIST, SHANGAI, RTS) is used for modelling. Results indicate the presence of volatility spillover from China and Russia stock markets to Turkish stock market., Uluslararası sermaye akımlarının serbestleştirilmesi ile birlikte günümüzde, tasarruf ve fonların en yüksek getiriyi sağlayacak sermaye piyasalarına serbestçe yönelmesi, farklı finansal piyasaları birbiriyle etkileşimli hale getirmiştir. En son gerçekleşen 2008 küresel finans krizi sonrasında, hisse senedi piyasalarında yaşanan dalgalanmalar uluslararası finansal yapıya yönelik tartışmaları da beraberinde getirmiştir. Bu çalışma, Çin ve Rusya hisse senedi piyasalarından Türkiye hisse senedi piyasasına oynaklık yayılımını incelemektedir. Bu kapsamda, günlük veriler ile 1 Ocak 2009 ve 9 Ağustos 2017 dönemi incelenmiş, dinamik koşullu çok değişkenli GARCH (DCC-MGARCH) modeli kullanılmıştır. Modelleme için her üç ülkenin hisse senedi piyasası fiyat endeksi (BIST, SHANGAI, RTS) verileri kullanılmıştır. Sonuçlar, Çin ve Rusya hisse senedi piyasalarından Türkiye hisse senedi piyasasına doğru oynaklık yayılımının varlığını işaret etmektedir.
- Published
- 2020
37. AVRUPA’DAKİ HAVA YOLU PAY SENETLERİNİN COVID-19 PANDEMİSİNE TEPKİSİ: OLAY ÇALIŞMASI METODOLOJİSİ
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Yiğit, Fatih, Canöz, İsmail, and İstanbul Ticaret Üniversitesi
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Olay Çalışması ,Event Study ,COVID-19 Pandemisi ,Abnormal Return ,The COVID-19 Pandemic ,Airline Stocks ,Hava Yolu Pay Senetleri ,Anormal Getiri - Abstract
The COVID-19 pandemic has struck all life, global economy, and financial markets. It stopped airline transportation in Europe and many regions of the world for a certain period as well as affecting many businesses negatively. In this process, naturally, excessive losses occurred in stock markets. Airline stocks were among the most affected by this situation. From this point of view, this study analyzes 38 airline stocks traded in the stock markets of 14 European countries with “the event study methodology”. The main purpose is to compare the reaction of the airline stocks traded in the stock markets of these countries to the pandemic and to determine whether a statistically significant cumulative average abnormal return is provided from them. Accordingly, event windows are determined as short and long windows within the scope of the event study. The findings show that a statistically significant cumulative average abnormal returns for airline stocks in all countries occurred in the -50 +50 event window. Besides, in short event windows around the pandemic announcement on March 11, which is accepted as the event date in this study, airline stocks in some countries respond to the pandemic significantly, while others do not. COVID-19 salgını tüm yaşamı, küresel ekonomiyi ve finans piyasalarını olumsuz etkiledi. Avrupa’da ve dünyanın birçok bölgesindeki çoğu işletmeyi olumsuz etkilediği gibi havayolu taşımacılığını da belirli bir süre durdurdu. Bu süreçte doğal olarak borsalarda aşırı kayıplar yaşandı. Bu durumdan en çok etkilenenler arasında havayolu pay senetleri de bulunuyordu. Bu açıdan bakıldığında, çalışma 14 Avrupa ülkesinin borsalarında işlem gören 38 havayolu hissesini “olay çalışması metodolojisi” ile analiz etmektedir. Temel amaç, bu ülkelerin borsalarında işlem gören havayolu hisse senetlerinin pandemiye tepkisini karşılaştırmak ve bunların istatistiksel olarak anlamlı kümülatif ortalama anormal getiri sağlayıp sağlamadığını belirlemektir. Buna göre olay pencereleri, olay çalışması kapsamında kısa ve uzun pencereler olarak belirlenmiştir. Bulgular, -50 +50 olay penceresinde tüm ülkelerdeki havayolu hisse senetleri için istatistiksel olarak anlamlı kümülatif ortalama anormal getirilerin gerçekleştiğini göstermektedir. Ayrıca, bu çalışmada olay tarihi olarak kabul edilen 11 Mart salgın duyurusunun etrafındaki kısa olay pencerelerinde, bazı ülkelerdeki havayolu pay senetleri pandemiye önemli ölçüde tepki verirken bazıları vermemektedir.
- Published
- 2020
38. Kamu personel mevzuatı açısından psikolojik taciz olgusunun incelenmesi
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Yiğit, Fatih, Özer, Mehmet Akif, and Siyaset Bilimi ve Kamu Yönetimi Anabilim Dalı
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Kamu Yönetimi ,Public Administration ,Public institutions ,Public personnel ,Mobbing ,Civil servants - Abstract
Günümüzde henüz kullanımı yeni olan ve literatürde çok fazla kaynak teşkil etmeyen psikolojik tacizkavramı, gerek örgüt gerekse bireylerin çalışmalarında performanslarını etkileyen önemli biretmendir. Psikolojik tacizin kavramsal olarak iyi bir şekilde anlaşılması, nedenlerinin ortayakonulması ve etkilerinin bertaraf edilmesi kamu kurum ve kuruluşları, işletmeler ve örgütler içinönem arz etmektedir. Son yıllarda ülkemizde uluslar arası literatürden daha sonra başlamakla birliktegittikçe artan bilinç ve buna paralel olarak artan akademik çalışmalar psikolojik taciz olgusununoldukça kritik bir çalışma hayatı problemlerinden biri olduğunu ortaya çıkarmıştır. Ülkemiz çalışmahayatında her ne kadar kara Avrupası ve Anglo-sakson ülkeler kadar erken dönem çalışmalarına konuolmasa da son yıllarda giderek artan psikolojik taciz(mobbing) algısının kamu personel mevzuatıaçısından incelenerek eksikliklerin giderilmesine yönelik önerilerin sunulması amaçlanmaktadır. The concept of mobbing, which is still in use today and does not constitute much resources in the literature, is an important factor affecting the performance of both organizations and individuals in their work.Understanding mobbing in a conceptually good way, revealing its causes and eliminating its effects are important for public institutions and organizations, businesses and organizations.In recent years, increasing consciousness and increasing academic studies in our country, which started later than international literature, and in parallel with increasing academic studies have revealed that the phenomenon of psychological harassment is one of the critical working life problems removed.Although our country is not the subject of early studies in the working life of land Europe and Anglo-Saxon countries, the perception of psychological harassment (mobbing) in recent years has been examined in terms of public personnel legislation and the shortcomings proposals for elimination. 113
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- 2020
39. Challenges in Inventory Management and a Proposed Framework
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Yiğit, Fatih and Yalçın, Bahar
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ComputingMilieux_GENERAL ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Economy ,Inventory Management - Abstract
In today’s economy, efficient inventory management is vital for all companies. Business environment, which is considered as volatile, uncertain, complex, and ambiguous (VUCA), big savings can be achieved with efficient inventory management. Effective implementation and management of inventory management system is vital for a company’s success. The success of such implementation not only affects the profit but also customer satisfaction. The goal of this chapter is to summarize the challenges faced and propose a framework to overcome these challanges.
- Published
- 2020
40. AVRUPA’DAKİ HAVA YOLU PAY SENETLERİNİN COVID-19 PANDEMİSİNE TEPKİSİ: OLAY ÇALIŞMASI METODOLOJİSİ
- Author
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YİĞİT, Fatih, primary and CANÖZ, İ̇smail, additional
- Published
- 2020
- Full Text
- View/download PDF
41. A new Fuzzy C-Means and AHP-based three-phased approach for multiple criteria ABC inventory classification
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Yiğit, Fatih, primary and Esnaf, Şakir, additional
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- 2020
- Full Text
- View/download PDF
42. Nakit Tutma Oranının Finansal ve Kurumsal Belirleyicileri: Borsa İstanbul Üzerine Bir İnceleme
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YİĞİT, Fatih, primary
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- 2020
- Full Text
- View/download PDF
43. Contrarian Strategy or Relative Strength Strategy: An Evidence from The Turkish Stock Market in 2010s
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YİĞİT, Fatih, primary
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- 2020
- Full Text
- View/download PDF
44. Efficiency of the Major Borsa Istanbul Indexes: An Empirical Investigation about the Interaction between Corporate Governance and Equity Prices Through a Market Model Approach
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YİĞİT, Fatih and MUZIR, Erol
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Kurumsal Yönetişim Kalitesi,Hisse Senedi Getirileri,Etkinlik,Borsa İstanbul ,İşletme ,Corporate Governance Quality,Stock Returns,Efficiency,Borsa Istanbul ,Management - Abstract
Bu çalışmada, kurumsal yönetişim kalitesi ve hisse senedi getirileriarasındaki bağlantı sorgulanmakta olup, Türkiye’deki önde gelen hisse senedipiyasa endeksleri ile kurumsal yönetişim arasındaki muhtemel bir ilişkiyiortaya çıkarmaya yönelik olarak endeks getirileri ile kurumsal yönetişimendeksi getirilerini basit piyasa modeli kullanılarak ilişkilendirmeye çalışannispeten farklı bir yaklaşım ortaya konulmuştur. Bununla birlikte, piyasaportföylerinin nispi etkinlik düzeylerinin, kurumsal yönetişim endeksineverdikleri tepkiler doğrultusunda karşılaştırılması amaçlanmıştır. Budoğrultuda, Kurumsal Yönetişim Endeksi’nin yanı sıra Borsa İstanbul’daki üçpiyasa endeksi - BİST 30, BİST 100 ve BİST TÜM - incelenmiş olup, En Küçük Kareler (EKK) ve Çok DeğişkenliUyumlu Regresyon Uzanımları (MARS) teknikleri kullanılarak söz konusu piyasaendeksi getirileri ile Kurumsal Yönetişim Endeksi getirileri arasındakiilişkiler modellenmiştir. Elde edilen bulgular, piyasa endeks getirileri ileKurumsal Yönetişim Endeksi getirileri arasında pozitif ve anlamlı bir ilişkiolduğunu göstermiş ve BİST 100 portföyünün BİST 30 ve BİST TÜM endeksportföylerine kıyasla daha etkin bir portföy olarak değerlendirilebileceğinedair bazı kanıtlar ortaya koymuştur., This paper is intended to argue the connection between corporategovernance quality and stock returns and aimed to present a slightly differentapproach to capturing relationship between the fundamental stock market indexesand corporate governance in Turkey by relating the major index returns to thecorporate governance index returns through a simple market model. Moreover, itis also aimed to compare relative efficiencies of the market portfoliosincluded to one another according to their reactional behaviors against thecorporate governance index. For this purpose, three market indexes in BorsaIstanbul, namely BIST 30, BIST 100 and BIST ALL as well as the CorporateGovernance Index (CGI) have been considered and analyzed. The returns on eachof these three market indexes are regressed on the returns of the corporategovernance index through the Ordinary Least Squares (OLS) and MultivariateAdaptive Regression Splines (MARS) techniques. Our findings suggest that themarket index returns are positively correlated with the corporate governanceindex returns and provide some evidence supporting the conclusion that the BIST100 index can be considered to be relatively efficient as compared to BIST 30and BIST ALL.
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- 2019
45. Doğalgaz Kullanılan Bir Trijenerasyon Sisteminin Enerji ve Ekserji Analizi
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YİĞİT, Fatih and KABUL, Ahmet
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Yerinde Enerji Üretimi,Trijenerasyon Sistemi,Termodinamik analiz ,Engineering, Multidisciplinary ,Mühendislik, Ortak Disiplinler ,In Place Energy Generation,Tri-generation Systems,Thermodynamic Analysis - Abstract
In this study, tri generation system which is one of the in place energy generation methods is analyzed thermodynamically by using EES (Engineering Equation Solve) software. The electricity capacity, exergy losses, and exergy efficiency was calculated which of the case study of consuming of 1000 m3 natural gas. In the pre-determined conditions, it is calculated that a trigeneration system which consumes 1000 m3 of natural gas per month has a capacity of generating the electrical energy of 3.018 kW, heating capacity of 10.12 kW and cooling capacity of 6.574 kW. It is calculated that such a trigeneration system which has such capacities of production has a thermal efficiency of 24%, COP of 0.68 and total exergy loss of 8.49 kW. The total loss of exergy at each system component has a percentage of; 28% at the boiler, 24% at the condenser I, 14% at the absorber, 12% at the generator 11% at the condenser II, 11% at the evaporator and 2% at the turbine respectively. These results that are obtained have shown resemblance with the results that have been published previously., Bu çalışmada, yerinde enerji üretimi yöntemlerinden olan trijenerasyon sisteminin EES (Engineering Equation Solve) yazılımı kullanılarak enerji ve ekserji analizi yapılmıştır. Tasarlanan trijenerasyon sisteminde aylık 1000 m3 doğal gaz kullanılması durumu için sistemin üretim kapasiteleri, ekserji yıkımları ve her bir elemanın ekserji verimleri hesap edilmiştir. Belirlenen çalışma şartlarında aylık 1000 m3 doğal gaz tüketen trijenerasyon sisteminin elektrik üretimi 3.018 kW, ısıtma kapasitesi 10.12 kW ve soğutma kapasitesi 6.574 kW olduğu hesap edilmiştir. Bu kapasitelerde üretim yapabilen trijenerasyon sisteminin ısıl verimin %24, COP’nin 0.68 ve toplam ekserji yokoluşunun 8.49 kW olduğu belirlenmiştir. Sistemin elemanlarının toplam yok olan ekserjideki payının sırasıyla kazanda %28, kondenser I’de %24, absorberde %14, generatörde %12, kondenser II’de %11 evaporatörde %9 ve türbinde %2 olduğu hesap edilmiştir. Elde edilen bu sonuçların literatürdeki benzer hesaplamalarda elde edilen bulgulara yakın olduğu belirlenmiştir.
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- 2019
46. Unraveling the Role of RDW in Predicting Early and Long-term Mortality following CABG Surgery.
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Adademir, Taylan, Yiğit, Fatih, Serbest, Hülya İlayda, and Büyükbayrak, Fuat
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CORONARY artery bypass ,ERYTHROCYTES ,IRON deficiency ,OXIDATIVE stress ,CARDIAC surgery - Abstract
Background: Red Cell Distribution Width (RDW) is a commonly used biomarker that assesses the variation in erythrocyte volume. Higher RDW levels are associated with conditions such as absolute iron deficiency, inflammation-induced iron sequestration, ischemia, and oxidative stress. These factors can contribute to unfavorable outcomes following cardiac surgery. While previous studies have explored the prognostic value of elevated RDW as a predictor of increased early and late mortality after Coronary Artery Bypass Grafting (CABG), it remains understudied in large-scale series within Turkey. Therefore, the objective of our research is to examine the predictive capability of RDW in relation to early and late-term mortality subsequent to CABG surgery. Metod: This study included all 1867 patients who underwent isolated Coronary Artery Bypass Grafting (CABG) surgery at our hospital between July 2011 and August 2013. The mean age of the patients was 60.4 ± 10.1 years (59.8 ± 9.9 years for males and 62.4 ± 10.7 years for females). Among the patients, 22.2% (n=414) were female. Early mortality was defined as deaths occurring within the first 30 days of hospitalization or within the hospital premises. Long-term mortality data were obtained through the mortality reporting system. The mean follow-up duration was 116.1 ± 6.8 months. Early mortality rate was 3.9% and the long-term mortality rate was determined as 29.6%. Mortality data were reevaluated based on patients preoperative RDW levels. Results: The overall mortality rate observed in this study was 32.4% (n=604), with an early mortality rate of 3.9% (n=72). The median RDW value for all patients was 14.8% (14.1-15.8). Significantly higher median RDW levels were observed in the subgroup of patients who experienced early mortality compared to those who survived (15.4% vs 14.8%, p<0.05). To further investigate the relationship between RDW and mortality, the remaining patients were stratified into three groups based on preoperative RDW values: Group 1 (0-25th percentile), Group 2 (25-75th percentile), and Group 3 (>75th percentile). During the ten-year follow-up period, the survival rates were 74.7%, 72.3%, and 61.2% respectively for each group. Patients in Group 3 demonstrated significantly lower survival rates compared to the other groups (Table 1), indicating a long-term impact of elevated RDW levels on mortality (p<0.001). Univariate analysis revealed a statistically significant association between RDW levels and mortality prediction (p: 0.000; OR: 1.166 CI: 1.096-1.239). Conlcusion: Elevated RDW levels may be considered as a predictor for both early and late mortality following coronary artery bypass grafting (CABG) in the Turkish population too. However, the significance of normalizing RDW values during the preoperative period and its impact on mortality remains unknown, necessitating further extensive studies to elucidate this relationship. [ABSTRACT FROM AUTHOR]
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- 2023
47. Does Gender Influence Long-Term Outcomes in Coronary Artery Bypass Surgery? Unraveling the Hidden Impact.
- Author
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Adademir, Taylan, Yiğit, Fatih, Turp, İrem, and Büyükbayrak, Fuat
- Subjects
CORONARY artery bypass ,HOSPITAL mortality ,HOSPITAL care ,KAPLAN-Meier estimator ,DATA analysis - Abstract
Background: Numerous studies including our previous series have consistently shown an increased mortality rate among women compared to men following isolated coronary artery bypass graft (CABG) surgery. While the impact of gender on early mortality rates is widely acknowledged, conflicting findings exist regarding its effects on long-term outcomes. This study aims to elucidate the influence of gender on both early and long-term mortality rates following isolated CABG surgery. Methods: All patients who underwent isolated CABG surgery at our hospital between July 2011 and August 2013 were included in this study. Early mortality referred to deaths within the first 30 days or during hospitalization, while deaths occurring beyond this period were classified as long-term mortality. Long-term mortality data were obtained through the mortality reporting system. Patients were grouped according to gender, and mortality rates were analyzed in three categories: overall, early-stage, and long-term mortality, using Kaplan-Meier analysis. Results: A total of 1867 patients were included in this study, with 22.2% (n=414) being female. The mean age of female patients was 62.3 ± 10.6 years, which was significantly higher than that of male patients (59.7 ± 9.9 years) (p<0.001). The mean follow-up duration was 116.1 ± 6.8 months. During this period, a total of 604 patients (32.4%) died, with 154 (25.5%) of them being female. There was a statistically significant difference in overall mortality rates based on gender (Table 1) (p<0.05), with a higher mortality rate observed in females (37.3% vs 31.1%). In light of these findings, patients were further analyzed based on early and late mortality outcomes. Of the 72 patients who experienced early mortality, 26 (36.1%) were female. Early mortality rates were significantly higher in female patients compared to males (6.3% vs 3.2%) (p<0.05). However, the mean age of female patients who died early was similar to that of male patients (mean age of males: 67.74 ± 9.99 years, mean age of females: 68.04 ± 9.66 years) (p>0.05). After excluding patients with early mortality, a total of 1795 patients were followed for an average of 116.1±6.8 months. During the follow-up period, 532 patients (29.6%) died. The mortality rate was 33.1% (n=128) in females and 28.8% (n=404) in males. There was no statistically significant difference in long-term mortality between females and males (p>0.05). However, as seen in Table 2, the Kaplan-Meier curve shows a divergence in favor of males starting from the 72nd month. Conclusion: These findings suggest that once early-stage mortality cases are removed from the analysis, there is no statistically significant disparity in long-term mortality rates between genders. Nonetheless, the Kaplan-Meier curve demonstrates a notable divergence favoring male patients after the 72nd month, indicating a potential long-term impact. Further investigations are warranted to thoroughly understand the underlying factors contributing to this divergence. [ABSTRACT FROM AUTHOR]
- Published
- 2023
48. The Relationship Of Epicardial Fat Tissue And Some Hormone Levels Measured In The Preoperative Period With Postoperative Atrial Fibrillation.
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Tekin, Kudret Atakan, Yiğit, Fatih, Güneş, Ayhan, Zengin, Ahmet, Pençe, Halime Hanım, Karagöz, Ali, Aksoy, Rezan, and Rabuş, Murat Bülent
- Subjects
ATRIAL fibrillation diagnosis ,POSTOPERATIVE period ,RADIATION exposure ,ECHOCARDIOGRAPHY ,COMPUTED tomography - Abstract
Objective: The amount of epicardial adipose tissue (EAT) is associated with atrial fibrillation (AF). In the study, we measured epicardial adipose tissue thickness (EATT) and some hormone levels in the preoperative period in patients planned for coronary artery bypass grafting (CABG) surgery. We aimed to examine the relationship between these values and postoperative complications, especially postoperative atrial fibrillation (POAF). Methods: Between September 2020 and July 2021, 161 patients were included in the study. The patients' data were collected prospectively from their files. EATT was measured by echocardiogram (ECHO) and computed tomography (CT) and adiponectin, leptin, and resistin hormone levels were measured in the preoperative period for patients undergoing CABG operation. The study evaluated the relationship between those levels and some postoperative complications in patients. Results: A total of 161 patients, 130 male (80.7%) and 31 female (19.3%), were included in the study. The mean age was 61±9 years, body mass index (BMI) was 28.72±5.22 kg/m², and the waist circumference was 100.5±11.1 cm. POAF developed in 29 of the patients (18.0%). There was a statistically significant difference in terms of EATT and left ventricle end-diastolic diameter between the group with POAF and the groups without POAF (EATT in the group with POAF: 6.4±1.9 mm, EATT in the group without POAF: 5.5±1.8 mm) (p<0.05). In multivariate logistic regression analysis, epicardial adipose tissue thickness was shown to be an independent predictor factor in the development of POAF (OR: 1.24, CI: 1.01-1.53, p=0.04). A statistically significant difference was found between EATT and BMI and waist circumference (p=0.002 and p<0.001, respectively). Conclusions: Measuring EATT preoperatively can provide an idea about the development of POAF. A high correlation was found between EATT values measured by CT and ECHO. In this regard, ECHO can be considered a good alternative to CT, which is the gold standard in EATT measurement. ECHO is more accessible, reproducible, and cost-effective without radiation exposure. [ABSTRACT FROM AUTHOR]
- Published
- 2023
49. Comparison Of Medium And Long-Term Outcomes Of Mitral Valve Surgery In Patients With Concomitant Ischemic Mitral Regurgitation Undergoing Isolated Coronary Artery Bypass Grafting.
- Author
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Yiğit, Fatih, Tekin, Kudret Atakan, Ak, Adnan, and Şişmanoğlu, Mesut
- Subjects
MITRAL valve surgery ,CORONARY artery bypass ,MITRAL valve insufficiency ,ECHOCARDIOGRAPHY ,CLINICAL trials - Abstract
Introduction: Ischemic mitral regurgitation can have a significant impact on morbidity and mortality in patients undergoing coronary bypass surgery. There is ongoing debate over the treatment of moderate mitral regurgitation. In this study, we aimed to examine the mid- and long-term results of treating moderate ischemic mitral regurgitation. MATERIALS AND Methods: This retrospective, cross-sectional, observational study included 126 patients. We analyzed 52 patients in two groups: isolated CABG and CABG+MVR/r. We conducted early period, 1-year, and 5-year echocardiographic and survival analyses of the patients. Results: Our analysis revealed that patients who underwent isolated CABG had higher mitral regurgitation grades at the post-op 1st year (p<0.05), but there was no statistically significant difference in the 5-year follow-up (p>0.05). There was no significant difference between the two groups in terms of 1-year and 5-year survival. The number of revascularized vessels (p=0.007, HR: 0.605 CI:0.421-0.869) and a history of postoperative cerebrovascular disease (p=0.001, HR: 20.794 CI:3.669-117.856) were independent predictive factors affecting survival. Conclusion: Our findings suggest that moderate ischemic mitral regurgitation management requires careful preoperative echocardiographic and clinical evaluation, and postoperative LV remodeling. Accurate quantification of the degree of mitral regurgitation and evaluation of all treatment options in accordance with guideline recommendations are essential. [ABSTRACT FROM AUTHOR]
- Published
- 2023
50. Survival Beyond a Decade: Unveiling the Ten-Year Mortality Outcomes after CABG in Turkey.
- Author
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Adademir, Taylan, Güneş, Ayhan, Yiğit, Fatih, Büyükbayrak, Fuat, Sarıkaya, Sabit, and Kırali, Kaan
- Subjects
CORONARY artery bypass ,MORTALITY ,HOSPITAL care ,DATA analysis - Abstract
BACKGROUND: Coronary artery bypass surgery is considered the gold standard treatment method for severe coronary artery disease and has been successfully applied in Turkey since the 1970s. Numerous studies have investigated early-term mortality following the operation. However, there is a lack of comprehensive research specifically addressing long-term mortality within the context of Turkey. The objective of our study is to elucidate the mortality rates after isolated CABG in our country and fill this important knowledge gap in the literature. Metod: All patients who underwent isolated CABG surgery at our hospital between July 2011 and August 2013 were included in the study. Early mortality was defined as deaths occurring within the first 30 days of hospitalization or within the hospital premises. Long-term mortality data were accessed through the mortality reporting system. Patients were reevaluated based on their age, gender, and the number of distal anastomoses performed during the operation. Results: Data of all 1867 patients who underwent isolated CABG surgery between July 2011 and August 2013 were checked through the mortality reporting system. The mean age of the patients was 60.4 ± 10.1 years (59.8 ± 9.9 years for males, 62.4 ± 10.7 years for females). 22.2% of the patients (n=414) were female. The mean follow-up duration was 116.1 ± 6.8 months. After excluding the data of 72 patients (26 females, 46 males) who had early mortality (3.9%), the long-term mortality rate was determined as 29.6% (n=532) (Table 1). In female patients, this rate was 33.1% (n=128), while in male patients, it was 28.8% (n=404) (p>0.05). The mortality rate in patients below 60 years old was 21,0%, whereas it was 36.4% in the age range of 60-75, and 57.3% in those aged 75 and above. Regarding the number of distal anastomoses performed during the operation, the long-term mortality rate was 37.6% (n=103/274) in patients who underwent single-vessel CABG, 27.9% (n=131/470) in those with two-vessel CABG, 30.2% (n=218/722) in those with three-vessel CABG, and 24.8% (n=80/322) in patients who received four or more grafts. Conclusion: The long-term mortality rates following isolated CABG in our country are comparable to those observed in developed countries. However, further extensive studies are needed to identify the factors influencing long-term mortality. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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