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Institution

Celal Bayar University

EducationMagnesia ad Sipylum, Turkey
About: Celal Bayar University is a education organization based out in Magnesia ad Sipylum, Turkey. It is known for research contribution in the topics: Population & Heat transfer. The organization has 2960 authors who have published 6024 publications receiving 100646 citations.


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Journal ArticleDOI
TL;DR: The thickness of total as well as superior and inferior quadrant peripapillary RNFL as measured by scanning laser polarimetry and tomography increased significantly with an increase in optic disc size and the total cross sectional area occupied by RNFL decreased significantly with a increase in age.
Abstract: Aims—To evaluate the relation of the optic nerve head topographic measurements and age with the thickness of the retinal nerve fibre layer (RNFL) in normal Caucasoid subjects by means of scanning laser polarimetry and tomography. Methods—Topographic optic disc measurements and RNFL thickness values of 38 normal Caucasoid subjects of both sexes aged 20 to 78 were measured using a confocal scanning laser ophthalmoscope and a confocal scanning laser polarimeter. One eye was randomly selected for statistical analysis.The eVects of optic disc size, age, and optic disc head topographic measurements of total and regional RNFL thickness were evaluated. Results—Age showed a significant correlation with the integral of the total RNFL thickness (R=˛0.341, p 0.05). Conclusion—The thickness of total as well as superior and inferior quadrant peripapillary RNFL as measured by scanning laser polarimetry increased significantly with an increase in optic disc size. The cross sectional area occupied by superior and inferior polar RNFL increased significantly with an increase in NRA. The total cross sectional area occupied by RNFL decreased significantly with an increase in age. The eVects of optic disc size, age, and NRA should be considered when the peripapillary RNFL thickness is evaluated. (Br J Ophthalmol 2000;84:473‐478)

42 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated whether domestic innovation reduces environmental degradation in Turkey by using the ARDL bounds test and threshold cointegration test, and found that the relationship between CO2 emission level and number of domestic patents depicts an inverted U-shape curve for Turkey.
Abstract: The study aims to investigate whether domestic innovation reduces environmental degradation in Turkey. Since the empirical literature on this subject is relatively poor and there is no empirical evidence for the Turkish case, the study attempts to bring a new perspective to the existing literature. To do this, the study estimates the relationship between innovation and CO2 emissions over the period of 1971–2013, via the ARDL bounds test and threshold cointegration test. Empirical results obtained from the ARDL approach indicates that the relationship between CO2 emission level and number of domestic patents depicts an inverted U-shape curve for Turkey. Moreover, estimation results show that urbanization, income level and financial development have positive effects on CO2 emissions, while alternative energy sources and human capital negatively affect the emission level. Since the linear econometric methods may yield inconsistent and biased results in the presence of a nonlinear relationship, the threshold cointegration method is employed as a robustness check. The findings obtained from threshold cointegration confirm the existence of a nonlinear relationship between CO2 emissions and domestic innovation. This suggests that for early stages of economic development, increases in domestic innovation raise the CO2 emission level in Turkey, but after achieving a certain development level, increases in domestic innovation lead to decreases in CO2 emissions. Thus, either developing or developed countries can eventually reduce CO2 emission levels by concentrating on innovation. Policy makers and institutions dealing with environmental issues should certainly pay attention to innovation and technological progress to assure a sustainable growth path.

42 citations

Journal ArticleDOI
TL;DR: A novel fuzzy portfolio selection model that takes into accounts the risk preferences in accordance with the market moving trends as well as the risk-return tradeoff, and allows the decision makers to define a certain importance and priority among their objectives is introduced.
Abstract: A novel fuzzy portfolio selection approach is proposed.This approach is based on the fuzzy goal programming techniques.Portfolio return, risk and beta coefficient are defined as the fuzzy goals.This approach allows defining certain importance and priority among fuzzy goals.The proposed approach considers the risk preferences of investor and market trend. Despite the risk-return tradeoff is main concern of financial theory; the rational investment decisions requires considering many criteria simultaneously. In addition to determining a certain importance and priority among these criteria, modeling the investor behaviors in accordance with market trends provides much more realistic approach. However, the researchers mostly overlook to evaluate these concepts simultaneously. This article introduces a novel fuzzy portfolio selection model that takes into accounts the risk preferences in accordance with the market moving trends as well as the risk-return tradeoff, and allows the decision makers to define a certain importance and priority among their objectives. To construct this model, firstly the portfolio return, risk and beta coefficient are assumed as main objectives including the possibilistic uncertainties. To define possibilistic uncertainty, the specific fuzzy membership functions are constituted for these objectives with respect to the risk preferences of investors and market moving trends. By means of the fuzzy goal programming techniques, a novel portfolio selection model is developed using these specific fuzzy membership functions. In the application section, three investment terms are examined in the Istanbul Stock Exchange National 30 Index. While ISE30 index has the upward (bullish) and the downward (bearish) moving trends in the first two implementations, the third implementation includes a scenario in which the investors desire to chase the ISE30 index. In the analyses, the proposed model is compared with the classical Mean-Variance, Mean-Absolute-Deviation and Maxmin models in terms of their portfolio returns based on the selling prices in the test periods. As a result, the proposed model gives superior performance than the classical models because it takes into account the investor preferences in accordance with market moving trend.

42 citations

Journal ArticleDOI
TL;DR: In this paper, an input oriented DEA model is constituted to focus on the efficient use of inputs, and the method is applied to the irrigation districts having similar types of agriculture in the Buyuk Menderes Basin, Turkey.
Abstract: While extending irrigated areas to augment agricultural production, irrigation efficiency should be increased not only to improve the agricultural production but also to obtain the sustainable use of valuable and limited water resources. Through the use of Data Envelopment Analysis (DEA), which is a linear programming technique to determine the relative efficiency of a decision-making unit, it is possible to decide whether the use of water in an irrigation district is efficient or not. In this study, an input oriented DEA model is constituted to focus on the efficient use of inputs, and the method is applied to the irrigation districts having similar types of agriculture in the Buyuk Menderes Basin, Turkey. This paper aims to determine the efficient irrigation district(s), in other words where the application of water is the most profitable, considering two inputs; water volume supplied and the total irrigated area, and one output, the total value of agricultural production. The weight restrictions consistent with decision makers’ value judgements are added as constraints into the DEA models to prevent excessive weight flexibility assigned to inputs and outputs. The results have provided the efficiency scores of the irrigation districts and numerically delineated desired features of the irrigation districts for maximum efficiency. The analyses for three study years have inferred the robustness of the results. It is concluded that DEA is a practical tool for detecting local inefficiencies and proposing possible improvements for irrigation districts that could offer the greatest potential for growth.

42 citations

Journal ArticleDOI
TL;DR: The results suggest that despite skin surface disinfection with PI, there is still significant risk for contamination of needles and catheters during epidural catheterization.

42 citations


Authors

Showing all 3053 results

NameH-indexPapersCitations
Michael Berk116128457743
G. Raven114187971839
Tjeerd Ketel99106746335
Francesco Dettori95102641313
Manuel Schiller95100441734
John A. McGrath7563124078
E. Pesen5020610958
Devendra Singh4931410386
Fatih Selimefendigil431784522
Mehmet Karabacak401113515
Nurullah Akkoc381937626
Daiana Stolz382397708
Menemşe Gümüşderelioğlu341363328
Mehmet Sezer341843543
Mehmet Pakdemirli331373581
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202332
2022100
2021512
2020485
2019372
2018359