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Search Results: 1 - 10 of 47 matches for " Seref Istek "
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Anisometropia Magnitude and Amblyopia Depth in Previously Untreated Unilateral Amblyopia Patients  [PDF]
Seref Istek
Open Access Library Journal (OALib Journal) , 2017, DOI: 10.4236/oalib.1103565
Abstract:
Objective: The study aimed to investigate the association among the depth of amblyopia, the magnitude of anisometropia, age, sex and laterality. Methods: A retrospective review of 13,146 patients was performed and 64 patients with unilateral anisometropic amblyopia were investigated between January 2013 and May 2015 in Hakkari Government Hospital Eye Clinic during my obligatory duty as an ophthalmologist. The depth of amblyopia, the magnitude of refractive error and anisometropia, age, laterality and gender of the patients were statistically analyzed. Results: Age was positively correlated with the cylindrical values of myopic amblyopic patients whereas such correlation was not observed in hyperopia (rho: 0.666; p < 0.01; Correlation is significant at the 0.01 level, 2-tailed). The amblyopia depth was significantly more common in the left eye compared to the right eye in severe and moderate amblyopia groups. In astigmatism, cylindrical powers of amblyopic eyes were statistically correlated with logMAR visual acuities of amblyopic eyes. The spherical powers of amblyopic eyes were statistically correlated with logMAR visual acuity of amblyopic eyes in myopia and in hyperopia. Also in hyperopia, cylindrical powers of healthy eyes were statistically correlated with cylindrical powers of amblyopic eyes (rho: 0.763; p < 0.01). This result may indicate the tendency of making amblyopia in both eyes of hyperopia patients. Conclusion: Refractive disorder difference of 0.75 diopter (D) astigmatism or 1.5 D of spherical refractive disorder difference was enough for amblyopia development. The same amount of anisohyperopia and anisoastigmatism leads to deeper amblyopia compared to the same amount of anisomyopia. The vision per D values of refractive disorders were approaching to each other above 4 D of spherical equivalents. The deeper amblyopia was significantly more common in the left eye compared to the right eye. The hyperopia seems to change slowly whereas the astigmatism and the myopia behave like a factor that varies as time goes by.
Innovation and Investment: Nasdaq-Listed Companies of Israel  [PDF]
Mustafa Seref Akin
Technology and Investment (TI) , 2010, DOI: 10.4236/ti.2010.14031
Abstract: Using a cross-section of Nasdaq-listed Israeli companies, we examine the impact of R & D spending on their market values and the ecosystem for start-ups in Israel. We find a very strong positive association between the two, learning that $1 million of spending in R & D associated with an increase of $5 million of market value. Among all countries outside the U.S., Israel is third after Canada and China in terms of the number of stocks registered on Nasdaq. Since 1981, sixty-one companies have registered, and their total R & D spending in 2009 reached $3.750 billion, which is approximately equal to the total R & D expenditure of Turkey. In the region, Middle Eastern and North African (MENA) countries cannot accomplish to register in Nasdaq. Israel’s great success comes from the strong dedication and cooperation between private and public sectors in research and venture capital. Israel spends 4.7% of its GDP for R & D, which is equal to the total expenditure of MENA.
Does Venture Capital Spur Patenting? Evidence from State-Level Cross-Sectional Data for the United States  [PDF]
Mustafa Seref Akin
Technology and Investment (TI) , 2011, DOI: 10.4236/ti.2011.24030
Abstract: We test the venture capital and patenting hypothesis state-level cross-section data for the United States, whereas previous research has been industry and firm based. We categorize R&D funds (federal research, industry research and academic research funds). We include the income level (gdp per capita) and size of the states (gdp, population, civilian labor force). We consider human capital factors as adding science and research holders of each state through different categories (doctoral sciences and engineering degree holders, graduate students of science and engineering, post doctorate students). Finally, we include the grants received by the Small Business Innovation Center. Even after controlling so many variables, our results suggest that venture funding has a strong positive impact on patenting in state-level cross-section data. A one billion dollar increase in venture capital is associated with an increase in 440 patents whereas a one billion dollar increase in corporate R&D is associated with an increase in 140 patents. Kortum and Lerener [1] find that a dollar of venture capital is seven times more powerful in stimulating pattern than a dollar of corporate R&D. Our research suggests that this difference is three times.
Effect of Activities of Daily Living on Self-Care Agency in Individuals with Type 2 Diabetes  [PDF]
Neslihan Istek, Papatya Karakurt
Journal of Diabetes Mellitus (JDM) , 2016, DOI: 10.4236/jdm.2016.64026
Abstract: Diabetes mellitus continues to be a global health problem with increasing importance across the world by affecting the activities of daily living and self-care ability of patients due to its incidence and troubles caused by it. The present study aims at determining the effect of activities of daily living of patients with type 2 diabetes mellitus on their self-care agency. Methods: The population of this descriptive study consisted of patients with type 2 diabetes mellitus who were being treated at the internal medicine clinic of a provincial state hospital between July 2014 and November 2015 and its sample consisted of 150 diabetic patients who volunteered to take part in the study and who were open to communication. A personal information form, the Activities of Daily Living (ADL) Scale, the Instrumental Activities of Daily Living (IADL) Scale and the Self-Care Ability Scale (CAS) were used as data collecting tools. The data were analyzed using descriptive statistics (numbers, percentages, mean, standard deviation, mean rank and frequencies), the Shapiro-Wilk, Kruskal-Wallis Variance Analysis, Mann-Whitney U test and Cronbach’s alpha formula and correlation analysis. Results: Approximately 97.3% of the patients with type 2 diabetes stated that they were independent in ADL and 75.3% of them in IADL. The patients’ mean self-care ability score was found to be 83.85 ± 17.87 ADL and IADL were found to be affected by age, marital status, education, duration of disease, willingness to receive further education, and presence of another disease besides diabetes. There was a significant correlation between the self-care agency score and marital status, education, duration of disease, willingness to receive further education, presence of another disease besides diabetes, regular checking of blood sugar and compliance with diet. A significant positive correlation was found between the patients’ activities of daily living and their self-care agency. Conclusion: The patients’ activities of daily living were found to affect their self-care agency. The personal and disease-related characteristics of patients should be identified so that their self-care behaviors can be increased.
La culture fran aise dans la publicité turque
Seref Kara
Synergies Turquie , 2012,
Abstract: L’interculturel tend à devenir une problématique incontournable dans divers contextes et en FLE. P. Charaudeau (1987) définit ce terme comme les échanges, les supports entre cultures, entre civilisations différentes en mettant l’accent sur la perception qu’une communauté se construit sur une autre communauté. Notre travail a pour objectif de travailler cette notion en analyse de discours : quelles traces de l’interculturel? Quelles catégories pour l’appréhender? Dans un premier temps, notre étude portera sur des discours qui se donnent pour objet l’autre et montrera comment le discours construit l’autre et dans un deuxième temps, elle proposera de découvrir l’image que les Turcs se font de la France et l’image qu’ils se font de la langue et de la culture fran aises dans le cadre de publicités présentes dans la presse turque. Le corpus rassemble des publicités fixes parues en janvier / février 2011. Notre analyse porte sur l’identification des clichés correspondant à la reconnaissance des valeurs composant l’identité d’une société. Les références à la culture fran aise sont multiples. Notre démarche théorique proposée est liée à la sémiologie : l’analyse des éléments iconiques et linguistiques dont l’interprétation connotative et l’organisation mettent en évidence les valeurs- exprimées ou suggérées- associées à la culture de l’autre.
Synthesis of ammonium silicon fluoride cryptocrystals on silicon by dry etching
Seref Kalem
Physics , 2004, DOI: 10.1016/j.apsusc.2004.05.008
Abstract: Cryptocrystal layers of ammonium silicon fluoride (NH4)2SiF6 were grown on silicon wafers by dry etching using the vapors of HF:HNO3 solution at room temperature. As-grown layers are composed of white granular crystalline film with thicknesses of up to 8 micrometer which were synthesized with growth rates of around 1 micron/hour. The crystallinity was analysed by X-ray diffraction which indicates an isometric hexoctahedral system(4/m -32/m) with Fm3m space grouping of (NH4)2SiF6 cryptohalite crystals. These results have been confirmed by the presence of the vibrational absorption bands of (NH4)2SiF6 species by FTIR transmission. Strong absorption bands were observed in the infrared at 480cm-1, 725cm-1, 1433cm-1 and 3327cm-1 and assigned to N-H and Si-F related vibrational modes of (NH4)2SiF6. Annealing above 150oC leads to the formation of individual crystals with sizes up to 20 micrometer on the surface, thus indicating the posibility of forming solid compound layers with fine grain sizes on silicon.
Controlling photon emission from silicon for photonic applications
Seref Kalem
Physics , 2015,
Abstract: The importance of a photon source that would be compatible with silicon circuitry is crucial for data communication networks. A photon source with energies ranging from UV to near infrared can be activated in Si as originationg from defects related to dislocations, vacancies, strain induced band edge transitions and quantum confinement effects. Using an etching method developed in this work, one can also enhance selectively the UV-VIS, band edge emission and emissions at telecom wavelengths, which are tunable depending on surface treatment. Deuterium D2O etching favors near infrared emission with a characteristic single peak at 1320 nm at room temperature. The result offers an exciting solution to advanced microelectronics The method involves the treatment of Si surface by deuterium Deuterium containing acid vapor, resulting in a layer that emits at 1320 nm. Etching without deuterium, a strong band edge emission can be induced at 1150 nm or an emission at 1550 nm can be created depending on the engineered surface structure of silicon. Schottky diodes fabricated on treated surfaces exhibit a strong rectifying characteristics in both cases.
Generating One Biometric Feature from Another: Faces from Fingerprints
Necla Ozkaya,Seref Sagiroglu
Sensors , 2010, DOI: 10.3390/s100504206
Abstract: This study presents a new approach based on artificial neural networks for generating one biometric feature (faces) from another (only fingerprints). An automatic and intelligent system was designed and developed to analyze the relationships among fingerprints and faces and also to model and to improve the existence of the relationships. The new proposed system is the first study that generates all parts of the face including eyebrows, eyes, nose, mouth, ears and face border from only fingerprints. It is also unique and different from similar studies recently presented in the literature with some superior features. The parameter settings of the system were achieved with the help of Taguchi experimental design technique. The performance and accuracy of the system have been evaluated with 10-fold cross validation technique using qualitative evaluation metrics in addition to the expanded quantitative evaluation metrics. Consequently, the results were presented on the basis of the combination of these objective and subjective metrics for illustrating the qualitative properties of the proposed methods as well as a quantitative evaluation of their performances. Experimental results have shown that one biometric feature can be determined from another. These results have once more indicated that there is a strong relationship between fingerprints and faces.
Surface properties of MDF coated with calcite/clay and effects of fire retardants on these properties
Istek,Abdullah; Aydemir,Deniz; Eroglu,Hudaverdi;
Maderas. Ciencia y tecnología , 2012, DOI: 10.4067/S0718-221X2012000200001
Abstract: the coating of wood and wood panel surfaces basically serves for surface protection and its surface can be improved at various user areas. different application methods are used for the coating of mdf surface. these are methods such as curtain coating, spraying, rolling, knife, etc. in this study, suitability of pigment coating method instead of the traditional surface coating methods used for coating mdf panels and the effects of fire retardants on surface properties of mdf coated by the best appropriate coating mixture was investigated. calcite and clay were used as coating pigment and latex, urea formaldehyde, and melamine formaldehyde were used as adhesive. coating/adhesive mixture obtained was applied to mdf panels with knives. before the analysis, test samples were put to condition room and they were kept in there for 1 week. according to the results obtained, the best appropriate coating material was found as calcite. 22% concentrated melamine formaldehyde as adhesive and 0.25 mm as coating thickness was determined better than other combinations. borax, boric acid and zinc borate as fire retardant were added to calcite /melamine formaldehyde with 22% mixture. so, the effects of fire retardant on surface characterization were determined. surface properties of coated mdf panels tested were found lower than standard requirements except for abrasion resistance.
Surface properties of MDF coated with calcite/clay and effects of fire retardants on these properties
Abdullah Istek,Deniz Aydemir,Hudaverdi Eroglu
MADERAS : Ciencia y Tecnología , 2012,
Abstract: The coating of wood and wood panel surfaces basically serves for surface protection and its surface can be improved at various user areas. Different application methods are used for the coating of MDF surface. These are methods such as curtain coating, spraying, rolling, knife, etc. In this study, suitability of pigment coating method instead of the traditional surface coating methods used for coating MDF panels and the effects of fire retardants on surface properties of MDF coated by the best appropriate coating mixture was investigated. Calcite and clay were used as coating pigment and latex, urea formaldehyde, and melamine formaldehyde were used as adhesive. Coating/adhesive mixture obtained was applied to MDF panels with knives. Before the analysis, test samples were put to condition room and they were kept in there for 1 week. According to the results obtained, the best appropriate coating material was found as calcite. 22% concentrated melamine formaldehyde as adhesive and 0.25 mm as coating thickness was determined better than other combinations. Borax, boric acid and zinc borate as fire retardant were added to calcite /melamine formaldehyde with 22% mixture. So, the effects of fire retardant on surface characterization were determined. Surface properties of coated MDF panels tested were found lower than standard requirements except for abrasion resistance.
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