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Search Results: 1 - 10 of 4672 matches for " Mehmet Onur Kaya "
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Darboux Slant Ruled Surfaces
Mehmet ?nder,Onur Kaya
Mathematics , 2013,
Abstract: In this study, we introduce Darboux slant ruled surfaces in the Euclidean 3-space which is defined by the property that the Darboux vector of orthonormel frame of ruled surface makes a constant angle with a fixed, non-zero direction. We obtain the characterizations of Darboux slant ruled surfaces regarding the conical curvature kappa and give the relations between Darboux slant ruled surfaces and some other slant ruled surfaces.
Characterizations of Slant Ruled Surfaces in the Euclidean 3-space
Mehmet ?nder,Onur Kaya
Mathematics , 2013,
Abstract: In this study, we give the relationships between the conical curvatures of ruled surfaces drawn by the unit vectors of the ruling, central normal and central tangent of a regular ruled surface in the Euclidean -space. We obtain the differential equations characterizing slant ruled surfaces and if the reference ruled surface is a slant ruled surface, we give some conditions for the surfaces drawn by the central normal and the central tangent vectors to be slant ruled surfaces.
Eikonal Slant Helices and Eikonal Darboux Helices In 3-Dimensional Riemannian Manifolds
Mehmet ?nder,Evren Ziplar,Onur Kaya
Mathematics , 2013, DOI: 10.1142/S0219887814500455
Abstract: In this study, we give definitions and characterizations of eikonal slant helix curves, eikonal Darboux helices and non-normed eikonal Darboux helices in three dimensional Riemannian manifold 3 M . We show that every eikonal slant helix is also an eikonal Darboux helix. Furthermore, we obtain that if the curve a is a non-normed eikonal Darboux helix, then a is an eikonal slant helix if and only if k 2 +t 2 = constant, where k and t are curvature and torsion of a, respectively.
Association of Serum YKL-40 Level with Tumor Burden and Metastatic Stage of Prostate Cancer
Enver Ozdemir,Tar?k Cicek,Mehmet Onur Kaya
Urology Journal , 2012,
Abstract: PURPOSE: To investigate the relationship between serum level of YKL-40 and Gleason score, grade and stage of the disease, and for the first time, with tumor burden in patients with prostate cancer (PCa). MATERIALS AND METHODS: Serum levels of YKL-40 and prostate-specific antigen were measured in 34 men (mean age: 66 years) with newly diagnosed and untreated PCa, in 34 men (mean age: 65 years) with biopsy proven benign prostatic hyperplasia, and in 29 healthy young men (mean age: 24 years). RESULTS: Serum YKL-40 concentration in men with PCa and benign prostatic hyperplasia, and in controls were 165.67 ± 107.84 ng/mL, 137.38 ± 82.04 ng/mL, and 69.69 ± 18.46 ng/mL, respectively. Serum level of YKL-40 was correlated with tumor burden in 30.4% of the patients with PCa (P = .04). A cut-off serum YKL-40 value of 92.696 ng/mL produced 70.6% sensitivity and 93.1% specificity. Elevated serum level of YKL-40 was strongly associated only with metastatic stage of the PCa. No association was observed between elevated level of YKL-40 and Gleason score groups or Gleason grade. CONCLUSION: Our results suggest that elevated serum level of YKL-40 may be a useful indicator of tumor burden and metastatic stage of PCa. Further studies are warranted to better elucidate the meaning of YKL-40 in tumor burden and invasiveness.
Acute Acalculous Cholecystitis due to Viral Hepatitis A
Safak Kaya,Ahmet Emre Eskazan,Nurettin Ay,Birol Baysal,Mehmet Veysi Bahadir,Arzu Onur,Recai Duymus
Case Reports in Infectious Diseases , 2013, DOI: 10.1155/2013/407182
Abstract: Inflammation of the gallbladder without evidence of calculi is known as acute acalculous cholecystitis (AAC). AAC is frequently associated with gangrene, perforation, and empyema. Due to these associated complications, AAC can be associated with high morbidity and mortality. Medical or surgical treatments can be chosen according to the general condition of the patient, underlying disease and agent. Particularly in acute acalculous cholecystitis cases, early diagnosis and early medical treatment have a positive effect on the patient and protect them from surgical trauma. ACC is a rare complication of acute viral hepatitis A. Herein, we present an adult patient of acalculous cholecystitis due to acute viral hepatitis A. She responded to the conservative management. 1. Introduction Hepatitis A is generally an acute, self-limited infection of the liver by an enterically transmitted hepatitis A virus (HAV). Infection may be asymptomatic or result in acute hepatitis, and rarely, fulminant hepatitis can ensue. Recognized complications of hepatitis A include cholestasis, prolonged and relapsing disease, fulminant hepatitis, and triggering of chronic active autoimmune extrahepatic disease [1]. Acute acalculous cholecystitis (ACC) is a rare complication of acute viral hepatitis [2]. Although the origin is obscure, demonstrated invasion of the gallbladder and bile duct epithelium by HAV and cell-mediated immunologic response have been proposed in the pathogenesis of HAV infection induced cholecystitis [3, 4]. Herein, we report a case of acalculous cholecystitis due to acute viral hepatitis A along with the published literature. 2. Case Report A 31-year-old female patient was admitted to the hematology department because of pancytopenia in February 2013. She had nausea, loss of appetite, back and joint pain, darkening of urine, and abdominal pain for 10 days. Her medical history was unremarkable. There was no history of medication or drug abuse. Physical examination showed body temperature of 37.5°C, heart rate of 92/minute, and blood pressure of 110/60?mmHg. Scleral icterus was present. The right side of the abdomen was tender with painful fullness in the right hypochondrium (a positive Murphy’s sign). Her liver was painful and palpable 3?cm under right costal margin. After examination, she was referred to general surgery with a diagnosis of acute cholecystitis, and surgery was planned. Laboratory investigations revealed microcytic anemia, leukopenia, and thrombocytopenia, elevated levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST),
Power Control for User Cooperation
Onur Kaya,Sennur Ulukus
Mathematics , 2006,
Abstract: For a fading Gaussian multiple access channel with user cooperation, we obtain the optimal power allocation policies that maximize the rates achievable by block Markov superposition coding. The optimal policies result in a coding scheme that is simpler than the one for a general multiple access channel with generalized feedback. This simpler coding scheme also leads to the possibility of formulating an otherwise non-concave optimization problem as a concave one. Using the channel state information at the transmitters to adapt the powers, we demonstrate significant gains over the achievable rates for existing cooperative systems.
Myocardial viability testing in patients with severe left ventricular dysfunction by SPECT and PET
Mehmet Onur Demirkol
Anadolu Kardiyoloji Dergisi , 2008,
Abstract: In this article, the role of nuclear medicine modalities in assessing myocardial viability and risk stratification in patients with advanced left ventricular (LV) dysfunction are reviewed. Diagnosis of reversible LV dysfunction in patients with heart failure is an important clinical issue. Patients with severe LV dysfunction who have viable myocardium are the patients at highest risk because of the potential for ischemia but at the same time benefit most form revascularization. It is important to identify viable myocardium in these patients, and nuclear medicine techniques are an excellent tool for this. Single-photon emission computed tomography (SPECT) in combination with myocardial perfusion tracers plays an important role in the identification of tissue viability in myocardial segments. Imaging with positron emission tomography (PET) tracers allow the assessment of physiologic processes such as myocardial oxygen consumption, metabolic rate of glucose utilization, and myocardial blood flow. Metabolic imaging with PET offers regional tissue viability in patients with advanced coronary artery disease and severely impaired LV function.
Power Control for Two User Cooperative OFDMA Channels
Sezi Bak?m,Onur Kaya
Mathematics , 2012,
Abstract: For a two user cooperative orthogonal frequency division multiple access (OFDMA) system with full channel state information (CSI), we obtain the optimal power allocation (PA) policies which maximize the rate region achievable by a channel adaptive implementation of inter-subchannel block Markov superposition encoding (BMSE), used in conjunction with backwards decoding. We provide the optimality conditions that need to be satisfied by the powers associated with the users' codewords and derive the closed form expressions for the optimal powers. We propose two algorithms that can be used to optimize the powers to achieve any desired rate pair on the rate region boundary: a projected subgradient algorithm, and an iterative waterfilling-like algorithm based on Karush-Kuhn-Tucker (KKT) conditions for optimality, which operates one user at a time and converges much faster. We observe that, utilization of power control to take advantage of the diversity offered by the cooperative OFDMA system, not only leads to a remarkable improvement in achievable rates, but also may help determine how the subchannels have to be instantaneously allocated to various tasks in cooperation.
Mehmet Fatih KAYA
Turkish Studies , 2011,
Abstract: In this study, focused on problems on this topic and how geography teachers develops the visual literacy skills on students at the highschools.This research is action research of the qualitative research methods. The study group of research, consists of twenty-geography teacher who serve in Gaziantep. The datas collected through the interview evaluated by descriptive analysis method.All of teachers according to datas where gets end of the research; are agrees that visual are given in many tectbooks and requirement of visual literacy. Most of teachers consider inadequate textbooks on prometing visual leteracy skills. Being different form the experince and knowledge of teachers that prometing visual skills leads to a different application to submit on geography lessons. In this research, tried to obtain problems on development of visual literacy skills Bu al mada, liselerde co rafya retmenlerinin rencilerde g rsel okuryazarl k becerilerini nas l geli tirdiklerini ve bu konuda kar la t klar sorunlar üzerinde durulmu tur.Bu ara t rma nitel ara t rma y ntemlerinden eylem ara t rmas desenindedir. Ara t rman n al ma grubu Gaziantep’te g rev yapan yirmi co rafya retmeninden olu maktad r. G rü me yoluyla elde edilen veriler betimsel analiz y ntemiyle de erlendirilmi tir. Ara t rma sonucunda elde edilen bulgulara g re retmenlerin tamam ; g rsel okuryazarl n gereklili i ve ders kitaplar n n ok say da g rsele yer verdi i konusunda hemfikirlerdir. retmenlerin büyük b lümü g rsel okuryazarl k becerisi kazand rmada ders kitaplar n yetersiz g rmektedir. retmenlerin deneyim ve bilgi birikimlerinin farkl olu u co rafya derslerinde g rsellerle ilgili beceri kazand rmada farkl uygulamalara yer vermelerine neden olmaktad r. Ara t rmada g rsel okuryazarl k becerisinin geli tirilmesinde kar la lan sorunlara ula lmaya al lm t r.
Mehmet Fatih KAYA
Turkish Studies , 2011,
Abstract: In this study, it was aimed to reveal views of geography teachers aboutstudents’ readiness level’s influence on geography education process.A semi-structured interview technique as one of qualitative researchmethods was utilized in this study. Sample of the study consisted of 17geography teachers that work in schools of Gaziantep city centre. Frominterviews extracted data was analysed by descriptive and content analysis.As a result of the research it has been determined that, as studentreadiness level at Anatolian Highschools are at sufficient level, its counterpart onnormal and vocational high schools is lower then expected. The main reasons ofthe lowness of the student readiness level was determined as student, parent,environment, class, class size, tools and administration based reasons. From thepoint of the research there has been made some suggestions. Bu al mada; co rafya retmenlerinin, rencilerin haz rbulunu luluk düzeylerinin co rafya e itim- retim sürecinde ne tür bir etkiyesahip oldu u konusundaki g rü lerinin ortaya konulmas ama lanm t r.Bu al mada, nitel ara t rma y ntemlerinden olan yar -yap land r lm g rü me tekni i kullan lm t r. Ara t rman n al ma grubunu Gaziantep ilmerkezinde g rev yapmakta olan 17 co rafya retmeni olu turmaktad r.G rü me yoluyla elde edilen veriler betimsel ve i erik analiz y ntemlerikullan larak analiz edilmi tir.Ara t rma sonucunda rencilerinin haz r bulunu luluklar n n Anadoluliselerinde yeterli düzeyde oldu u, düz ve meslek lise türlerinde ise istenendüzeyden dü ük oldu u saptanm t r. Haz r bulunu luluk düzeyinin yetersizli innedenleri; renci, veli, evre, s n f, s n f mevcudu, ara -gere ve y neticikaynakl oldu u tespit edilmi tir. Ara t rma sonu lar ndan hareketle baz nerilerde bulunulmu tur.
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