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Ankara, Turkey

Ankara University is a public university in Ankara, the capital city of Turkey. It was the first higher education institution founded in the Turkish Republic.The university has about 40 vocational programs, 114 undergraduate programs and 110 graduate programs. In total it has about 264 programs. Wikipedia.

This study was carried out on the Cappadocia section of the Kizilirmak river valley, the longest river completely within the borders of Turkey (1355km). A staircase of fifteen terraces found in the valley is maintained against erosion at elevations up to 160m above the current river level. The GülŞehir-Karaburna Quatenary Basalts (four basalt flows), which cap four terraces, were numerically dated for the first time using the Ar-Ar technique. The Evren Ridge Basalt (β1), +160m above the river level and capping Terrace 1, was dated to 1989.4±38.9ka. The Karaburna Basalt Plateau (β2) is +128m above the river level and caps Terrace 4, and was dated to 1228.2±46.4ka. The Tuzköy Basalt Plateau (β3), +29m above the river level and capping Terrace 12, was dated to 403.8±9.8ka, and the Karniyarik Hill Basalts (β4) at +4.5m above the river level and capping Terrace 15 were dated to 96.0±13.0ka. These basalt ages provide minimum ages for the underlying fluvial deposits. On the one hand, these data show that Kizilirmak River incised its valley by 160m during the last ~2Ma of its evolution. On the other hand, by using terrace sequences and basalt ages, the time-averaged incision rate of the river during the last 2Ma was determined as approximately 0.08mm/a-1, but important variations within that time span are also apparent. The highest incision rate during this period was determined to be 0.12mm/a-1 between the late Early and mid Middle Pleistocene. From the numerical chronology, terrace stratigraphy and paleosol records, it is suggested that the main incision phases of the Kizilirmak River led to terrace formation during the cold periods and the deposition phases occurred during the warm periods (including cold-warm transitions). As a result of assigning terraces to marine oxygen isotope stages, it was inferred that nearly all terrace levels had formed during the eccentricity-driven climate cycles, in association with high uplift rates, which were interpreted as being complete in the valley. © 2010 Elsevier B.V. Source

Efe M.O.,Ankara University
IEEE Transactions on Industrial Informatics | Year: 2011

This paper describes an emerging tool for industry: fractional order systems. Conventional understanding of the notion of derivative and integral uses integer orders and our sense is mature in their physical interpretations. Derivatives or integrals of fractional orders are generalizations of the concept containing the classical cases and solutions based on fractional order operators utilize the full flexibility offered by the mathematical definitions. The interest of the industry to fractional order systems lie in the fact that complicated modules can be simplified significantly and practical applications can be diverse. This paper describes linear and nonlinear cases with necessary stability and performance considerations for the benefit of a practicing engineer exploiting informatics in industry. © 2011 IEEE. Source

Kandemir B.S.,Ankara University
Journal of Physics Condensed Matter | Year: 2013

A theoretical investigation of the possible existence of chiral polaron formation in graphene is reported. We present an analytical method to calculate the ground-state of the electron-phonon system within the framework of the Lee-Low-Pines theory. On the basis of our model, the influence of electron-optical phonon interaction on the graphene electronic spectrum is investigated. We considered only the doubly degenerate optical phonon modes of E2g symmetry near the zone center Γ. It is analytically shown that the energy dispersions of both valence and conduction bands of the pristine graphene differ significantly from those obtained through the standard electron self-energy calculations arising from the electron-optical phonon interactions. In this paper, we also show for the first time that the degenerate band structure of the graphene promotes the chiral polaron formation. Furthermore, due to the k-dependent nature of the polaronic self-energy, in analogy with quantum chromodynamics, we also propose a running electron-phonon coupling constant as a function of energy. © 2013 IOP Publishing Ltd. Source

Ensari A.,Ankara University
Archives of Pathology and Laboratory Medicine | Year: 2010

Context.-Celiac disease, or gluten-sensitive enteropathy, is a chronic inflammatory disorder of the small intestine characterized by malabsorption after ingestion of gluten in individuals with a certain genetic background. Clinical presentation can vary from full-blown malabsorption to subtle and atypical symptoms. Diagnosis currently relies on clinicopathologic studies including mucosal biopsy, serologic tests, and the effects of a diet free of gluten on the symptoms. Mucosal pathologic features are also variable, ranging from mild abnormalities, including intraepithelial lymphocytosis, to completely flat mucosa. Since patients with minimal histologic lesion of intraepithelial lymphocytosis often present with normal serologic findings, biopsy diagnosis becomes more important for identifying such individuals. Classification of mucosal pathology in gluten-sensitive enteropathy has been a subject of controversy among pathologists and needs to be revised according to the current understanding of the disease. Objectives.-To highlight the variations in clinical and pathologic presentation of gluten-sensitive enteropathy, to emphasize the importance of small-intestinal biopsy evaluation in the diagnosis, and to propose a new classification of mucosal pathology in gluten-sensitive enteropathy, in an effort to overcome the problems related to the classification systems currently available. Data Sources.-A review of the literature on clinicopathologic features and the morphologic spectrum of gluten-sensitive enteropathy is presented. Conclusions.-Considering that there are many entities in the differential diagnosis of gluten-sensitive enteropathy, because of the varied clinicopathologic spectrum of the disease, diagnosis depends on good clinicopathologic communication. The classification that is presented in this review is a simple and practical approach to improve clinicopathologic correlation in gluten-sensitive enteropathy. Source

Yurdaydin C.,Ankara University
Seminars in Liver Disease | Year: 2012

Chronic delta hepatitis (CDH) remains the most progressive form of chronic viral hepatitis and as such its successful treatment is important. However, in striking contrast to the situation in chronic hepatitis B and C, no new drugs for its treatment have been introduced in the recent past and interferons remain the only evidence-based effective treatment of CDH. However, results are far from optimal. Overall, around 25 to 30% of patients may have a sustained response after one year of conventional or pegylated interferon (Peg-INF) treatment and such treatment may favorably affect the natural history of the disease. The superiority of Peg-INF over its conventional form is possible, but has not been demonstrated in a clinical trial. Several unanswered questions remain in the context of INF treatment such as (1) the need for standardization of HDV-RNA quantitation, the most widely used surrogate marker of treatment efficacy; (2) validation of this treatment end point as an index of long-term containment of HDV; (3) optimal duration of treatment; (4) baseline and on-treatment parameters of treatment efficacy; and (5) development of new markers of treatment efficacy. Nucleos(t)ide analogs (NAs) have been widely tested in CDH, but they appear to be ineffective when used for a duration of up to 2 years. Combination treatment of NAs with INFs also proved to be disappointing. New approaches to treatment are hepatocyte entry inhibitors and prenylation inhibitors to be hopefully tested in human CDH in the not-too-distant future. Copyright © 2012 by Thieme Medical Publishers, Inc. Source

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