Browsing by Author "Karaca, I"

Now showing 1 - 20 of 27
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    Relative Homology Groups of Digital Images
    Ege, O; Karaca, I; Ege, ME
    In this paper we are interested in relative homology groups of digital images. Some properties of the Euler characteristics for digital images are given. We also present reduced homology groups for digital images. The main purpose is to obtain some differences between notions in digital topology and algebraic topology.
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    Digital Fibrations
    Ege, O; Karaca, I
    In this paper, digital fibrations were introduced. Theorems related to digital fibrations were proved. Homology properties of digital fibrations with counter examples were studied and an application for digital fibrations was also described.
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    Banach fixed point theorem for digital images
    Ege, O; Karaca, I
    In this paper, we prove Banach fixed point theorem for digital images. We also give the proof of a theorem which is a generalization of the Banach contraction principle. Finally, we deal with an application of Banach fixed point theorem to image processing. (C) 2015 All rights reserved.
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    Computing Higher Dimensional Digital Homotopy Groups
    Meric, ET; Vergili, T; Karaca, I
    In this paper, we study out a method for computing digital homotopy groups in higher dimensions. We investigate the relation between a digital image and its nth homotopy group when n is greater than 1 and show that a digital covering map which is a radius 2 local isomorphism induces an isomorphism between digital homotopy groups in higher dimensions.
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    Isolated esophageal atresia with spontaneous recanalization
    Günsar, C; Sencan, A; Karaca, I; Mir, E
    Isolated esophageal atresia is characterized by a long segment between the 2 esophageal pouches. The authors describe a case of pure esophageal atresia that showed spontaneous recanalization in the waiting period for primary esophageal anastomosis. Regurgitation of gastrostomy formula surprisingly was seen in her mouth. The patency of the esophagus was confirmed with thoracic computed tomography (CT) and an esophagogram. A strictured area in the proximal upper third of the esophagus was managed with baloon dilatation. She was discharged in normal condition, feeding by mouth, and with a normal esophagogram. This interesting event led us to speculate about a different type of pure esophageal atresia with the feasibility of the ends recanalizing after some events such as inflammation. This could be the subtype 115 of type 2 in Kluth's atlas of esophageal atresia in which they described 2 blind esophageal ends and a cyst occupying the intervening space. Another speculation about this subject is the presence of double membranes associated with esophageal atresia with a normal outer appearance of the esophagus as was first described by A. F. van Loosbroek, Copyright 2002, Elsevier Science (USA), All rights reserved.
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    Pyloric atresia associated with multiple intestinal atresias and pylorocholedochal fistula
    Sencan, A; Mir, E; Karaca, I; Günsar, C; Sencan, A; Topçu, K
    Although congenital pyloric atresia commonly occurs in isolation, it has rarely been reported in association with other alimentary tract atresias. This is a report of a newborn with congenital pyloric atresia associated with duodenal atresia, jejunal atresia, apple-peel ileal atresia, and pylorocholedochal fistula. Preoperative diagnosis was duodenal atresia because of bilious vomiting, and erect radiogram showed double bubble sign. The presented case is the first report of such an association. Copyright 2002, Elsevier Science (USA). All rights reserved.
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    The biochemical and histopathological effects of ursodeoxycholic acid and metronidazole on total parenteral nutrition-associated hepatic dysfunction
    Günsar, G; Melek, M; Karaca, I; Sencan, A; Mir, E; Orta, R; Canan, O
    Background/Aims: Total parenteral nutrition causes many complications such as cholestasis. Ursodeoxycholic acid is used for the treatment of several cholestatic problems. Metronidazole was investigated before for preventing some components of total parenteral nutrition-associated hepatic dysfunction. This study was designed to investigate the effects of ursodeoxycholic acid alone and ursodeoxycholic acid + metronidazole combination on total parenteral nutrition-associated cholestasis. Methodology: Eighteen rabbits were divided into three groups as follows: group A received a standard formula of total parenteral nutrition only, group B received total parenteral nutrition + ursodeoxycholic acid (3mg/kg/day), and group C were given total parenteral nutrition + ursodeoxycholic acid + metronidazole (25mg/kg/day) for eight days, respectively. Several parameters of liver function tests were compared among these groups. These were transaminases, alkaline phosphatase, total bilirubin, total cholesterol, triglycerides, and serum bile acids. Liver histology was detected in each group at the end of the experiment. Results: In group A, total parenteral nutrition administration resulted in remarkably higher serum values of transaminases, alkaline phosphatase, total cholesterol, total bilirubin, triglycerides, and free bile acids whereas ursodeoxycholic acid administration showed important improvements in the serum values of these parameters in group B animals. The metronidazole group showed nearer or similar laboratory values with group B, but significant differences appeared in bilirubin values (P<0.05) among these groups. Liver histology presented marked differences between group A and group B. Steatosis formed the main component of liver histology in 4 animals out of 6 in group A. Contrary to this, all of the specimens showed normal liver structure except one in group B. In the third group we did not see better morphology than in group B. Conclusions: These results suggested that oral ursodeoxycholic acid therapy during total parenteral nutrition reduces bilirubin levels and improves the other indicators of cholestasis and helps prevent disturbances of liver histology. When it is combined with metronidazole a significant decrease in bilirubin levels has been gained. With the help of ursodeoxycholic acid we can provide enterohepatic circulation of bile acids and regulate lipid metabolism. Metronidazole can be an antibiotic of choice during total parenteral nutrition when needed.
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    Investigation of the effects of physico-chemical environmental conditions on population fluctuations of Notonecta viridis Delcourt, 1909 (Hemiptera: Notonectidae) in Van Lake by using Zero-inflated generalized Poisson regression
    Yesilova, A; Özgökçe, MS; Atlihan, R; Karaca, I; Özgökçe, F; Yildiz, S; Kaya, Y
    In ecological studies, it is a common situation occured that population density of species extremly increases or decreases in certain periods depending on many abiotic and biotic factors. Because of ecologial factors that cause high level fluctuation in population density, It is possible to get zero individual at samplings, and on the other hand, differences between maximum and minimum values obtained in different samplings intervals can be very high. Because this type of data based on counting does not show normal distribution, and shape of the distribution is skewed to the right because of the abundance of zero, using the Zero-inflated Poisson regression method (ZIGP) is required. This study was carried out to obtain information on effects of physico-chemical environmental conditions on population fluctuation of Notonecta viridis. Samplings were conducted with monthly periods along the coastal band of Van Lake in 2005-2006. Samples were taken from 20 sampling places where have three different characters as stream entrances, settlements and natural coastlines. Reults were analysed by using ZIGP regression model. According to results, Effect of sampling intervals and sampling stations on population densities of Notonecta viridis were important. On the other hand, HCO3 had negative effect on population densities in zero-inflated model while it had possitive effect on population densities in other two models. It was determined that Fe effected the species populations in the negative way in the mean regression model, and Cl and Mg effected it in possitive way in the overdispersion regression. In the result, it was deductived that Notonecta viridis was found excessive numbers or none in some sampling stations because of the pysico-chemical structures of water.
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    SOME RESULTS OF THE NILPOTENCE IN THE MOD P STEENROD ALGEBRA
    Ege, O; Karaca, I
    In this paper, we deal with a collection of left and right ideals of A(p) which is the mod p Steenrod algebra. We also prove that for all odd prime numbers p, the nilpotence heights of P-2P and P2P+1 are p and p - 1, respectively.
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    Simplicial homology groups of certain digital surfaces
    Ünver Demir, E; Karaca, I
    In this paper we compute the simplicial homology groups of some digital surfaces.
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    Digital homotopy fixed point theory
    Ege, O; Karaca, I
    In this paper, we construct a framework which is called the digital homotopy fixed point theory. We get new results associating digital homotopy and fixed point theory. We also give an application on this theory. (C) 2015 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
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    Applications of the Lefschetz Number to Digital Images
    Ege, O; Karaca, I
    The goal of this paper is to develop some applications of the Lefschetz fixed point theorem to digital images. We also deal with relative and reduced Lefschetz fixed point theorem for digital complexes. We give some examples related to the topic. We calculate the degree of the antipodal map for sphere-like digital images using fixed point properties.
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    Cohomology Theory for Digital Images
    Ege, O; Karaca, I
    In this paper we propose a mathematical framework that can be used for de fining cohomology of digital images. We state the Eilenberg-Steenrod axioms and the Universal Coefficient Theorem for this cohomology theory. We show that the Kunneth formula doesn't hold. A cup product is defined and its main properties are proved.
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    Atresia of the colon
    Etensel, B; Temir, G; Karkiner, A; Melek, M; Edirne, Y; Karaca, I; Mir, E
    Background/Purpose: Colonic atresia (CA) is one of the rarest causes of neonatal intestinal obstructions, and no large series can be reported. Therefore, we did perform a retrospective clinical trial to delineate our CA cases and carry out a literature survey. Methods: We reviewed the charts of CA cases treated in our center between 1992 and 2002. We aimed to collect all reported cases in Medline, and personal communications with the authors of published series were used to reach the missing data. Results: The chart review revealed 9 newborns with CA treated in our center (6 cases of type III, 2 cases of type II, and I case of type IV). These accounted for 3.7% of all gastrointestinal atresias managed in our center. Of the CA cases, 3 were isolated and 6 had at least one or more associated congenital anomalies. The preferred surgical technique at the initial treatment of CA was performing a proximal stoma and distal mucous fistula in an average of postnatal 59.4 hours. The literature survey enabled us to reach 224 cases of CA, including our cases. Conclusions: Because of the low incidence of CA, delay in diagnosis and treatment may occur. The mortality is statistically higher when the surgical management is performed after 72 hours of age. However, the prognosis of CA is satisfactory if diagnosis and surgical management could be made promptly and properly. (c) 2005 Elsevier Inc. All rights reserved.
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    GRAPH TOPOLOGY ON FINITE DIGITAL IMAGES
    Ege, O; Karaca, I
    The main goal of this work is to present a topology, called a graph topology, on finite digital images. We deal with some properties of this topology such as k-connectivity and digital continuous mapping. We finally show that the property of being graph topology is a topological invariant between digital isomorphic finite digital images.
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    Some properties of digital H-spaces
    Ege, Ö; Karaca, I
    In this paper, we study certain properties of digital H-spaces. We prove that a digital image that has the same digital homotopy type with any digital H-space is also a digital H-space. We show that the digital fundamental group of a digital H-space is abelian. We give examples that are related to a digital homotopy associative H-space and a kappa-contractible digital H-space. Several important applications of digital H-spaces are given in computer vision and image processing. Finally, we deal with the importance of digital H-space in digital topology and image processing. We conclude that any kappa-contractible digital image is a digital H-space.
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    Lefschetz fixed point theorem for digital images
    Ege, O; Karaca, I
    In this article we study the fixed point properties of digital images. Moreover, we prove the Lefschetz fixed point theorem for a digital image. We then give some examples about the fixed point property. We conclude that sphere-like digital images have the fixed point property.
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    Treatment and prophylaxis with sucralfate ameliorates hypoxia/reoxygenation-induced intestinal injury in pup rats
    Sencan, AB; Sencan, A; Aktas, S; Habif, S; Kabaroglu, C; Parildar, Z; Karaca, I
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    Digital fixed points, approximate fixed points, and universal functions
    Boxer, L; Ege, O; Karaca, I; Lopez, J; Louwsma, J
    A. Rosenfeld [23] introduced the notion of a digitally continuous function between digital images, and showed that although digital images need not have fixed point properties analogous to those of the Euclidean spaces modeled by the images, there often are approximate fixed point properties of such images. In the current paper, we obtain additional results concerning fixed points and approximate fixed points of digitally continuous functions. Among these are several results concerning the relationship between universal functions and the approximate fixed point property (AFPP).
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    Zooplankton composition of Van Lake Coastline in Turkey
    Yildiz, S; Özgökçe, MS; Özgökçe, F; Karaca, I; Polat, E
    This study was completed with periodical surveys in coastal band of Van Lake between May and September in 2005 to 2006 period. It was carried out on a total of 20 sites selected as sampling points and having three distinct characteristics. During the study, a total of 20 species (14 belonged to genus of Rotifera, 4 to Copepoda and 2 Branchiopoda) were found at the Van Lake coastal zone. Genera Notholca squamula, Keratella quadrata, Colurella colurus, Lecane ohiensis, Lecane grandis and Lecane lamellata have been detected for the first time at the Van Lake coastal zone.