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Öğe Anti-invariant submanifolds of locally decomposable golden Riemannian manifolds(Balkan Society of Geometers, 2020) Gök M.; Kiliç E.; Keleş S.In this paper, we give some properties of anti-invariant submanifolds of a golden Riemannian manifold. We obtain some necessary conditions for any submanifold in a locally decomposable golden Riemannian manifold to be anti-invariant. In these conditions, we also show that the submanifold is totally geodesic. We find a local orthonormal frame for the normal bundle of any anti-invariant submanifold of a locally decomposable golden Riemannian manifold. Finally, we demonstrate the existence of unit and mutually orthogonal normal vector fields such that their corresponding second fundamental tensors vanish identically under the assumption that the codimension of the anti-invariant submanifold is greater than its dimension. © Balkan Society of Geometers, Geometry Balkan Press 2020.Öğe Biharmonic hypersurfaces of LP-Sasakian manifolds(Universitatii Al.I.Cuza din Iasi, 2011) Perkta S.Y.; Kiliç E.; Keleş S.In this paper the biharmonic hypersurfaces of Lorentzian para-Sasakian manifolds are studied. We firstly find the biharmonic equation for a hypersurface which admits the characteristic vector field of the Lorentzian para-Sasakian as the normal vector field. We show that a biharmonic spacelike hypersurface of a Lorentzian para-Sasakian manifold with constant mean curvature is minimal. The biharmonicity condition for a hypersurface of a Lorentzian para-Sasakian manifold is investigated when the characteristic vector field belongs to the tangent hyperplane of the hypersurface. We find some necessary and sufficient conditions for a timelike hypersurface of a Lorentzian para-Sasakian manifold to be proper biharmonic. The nonexistence of proper biharmonic timelike hypersurfaces with constant mean curvature in a Ricci flat Lorentzian para-Sasakian manifold is proved.Öğe Effects of misoprostol on the endometrium of ovariectomized rats(2000) Sönmez A.S.; Birincio?lu M.; Aydin A.; Kiliç E.; Şahin N.Misoprostol (Cytotec, Searle, England), a prostaglandin E1 analogue, is indicated for protection of peptic disease induced by cyclo-oxygenase inhibitors. Since vaginal bleeding was reported during misoprostol use previously, we hypothesized that misoprostol might cause endometrial stimulation. Therefore, we investigated the effects of misoprostol on the endometrium of ovariectomized (OVX) rats to investigate any endometrial changes. Thirty-two, four month-old, parous female Sprague-Dawley rats were used in this study. All rats underwent ovariectomy at the beginning of the study. Sixty days after the ovariectomy six rats were sacrificed to remove the uterus and the remaining 26 rats were divided into three groups. Group I (six rats) was treated with vehicle (1 cc of distilled water orally) for 60 days. Groups II and II (ten rats each) were treated with oral 100 and 200 ?g/day misoprostol, respectively, for 60 days. At the end of the treatment laparotomy was performed and the uteri of all the rats were removed. Histopathologic examination of the endometrium 60 days after ovariectomy revealed endometrial atrophy. But after misoprostol administration a minimal endometrial proliferation was encountered regardless of the dose of misoprostol. The present study demonstrated that misoprostol can cause a proliferation in the endometrium after 60 days of administration. Long term studies are needed to evaluate if this proliferation leads to hyperplasia and cancer, especially in postmenopausal women.Öğe GENERAL ROTATIONAL SURFACES IN EUCLIDEAN 4-SPACE WITH GENERALIZED 1-TYPE GAUSS MAP(Canadian University of Dubai, 2023) Sağdiç M.; Turgay N.C.; Kiliç E.In this paper, we consider rotational surfaces in the Euclidean 4-space E4 with the profile curve contained in a 2-plane. We obtain some classification results of such surfaces in terms of having generalized 1-type Gauss map. © 2023, Canadian University of Dubai. All rights reserved.Öğe Hypersurfaces of lorentzian para-sasakian manifolds(Mathematica Scandinavica, 2011) Perktaş S.; Kiliç E.; Keleş S.In this paper we study the invariant and noninvariant hypersurfaces of (1, 1, 1) almost contact manifolds, Lorentzian almost paracontact manifolds and Lorentzian para-Sasakian manifolds, respectively. We show that a noninvariant hypersurface of an (1, 1, 1) almost contact manifold admits an almost product structure. We investigate hypersurfaces of affinely cosymplectic and normal (1, 1, 1) almost contact manifolds. It is proved that a noninvariant hypersurface of a Lorentzian almost paracontact manifold is an almost product metric manifold. Some necessary and sufficient conditions have been given for a noninvariant hypersurface of aLorentzian para-Sasakian manifold to be locally product manifold.We establish a Lorentzian para-Sasakian structure for an invariant hypersurface of a Lorentzian para-Sasakian manifold. Finally we give some examples for invariant and noninvariant hypersurfaces of a Lorentzian para-Sasakian manifold.Öğe Lightlike hypersurfaces of a semi-riemannian product manifold and quarter-symmetric nonmetric connections(2012) Kiliç E.; Bahadr O.We study lightlike hypersurfaces of a semi-Riemannian product manifold. We introduce a class of lightlike hypersurfaces called screen semi-invariant lightlike hypersurfaces and radical anti-invariant lightlike hypersurfaces. We consider lightlike hypersurfaces with respect to a quarter-symmetric nonmetric connection which is determined by the product structure. We give some equivalent conditions for integrability of distributions with respect to the Levi-Civita connection of semi-Riemannian manifolds and the quarter-symmetric nonmetric connection, and we obtain some results. © 2012 Erol Kl and Ouzhan Bahadr.Öğe Ligthlike ruled surfaces in ?14(2006) Kiliç E.; Karada? H.B.In this paper, we introduce the lightlike ruled surfaces in semi-Euclidean space ?14 and classify the lightlike ruled surfaces in ?14. It is also investigated that their induced connection is a metric connection. Furthermore, we give the conditions of becoming striction line of base (directrix) curve. © Balkan Society of Geometers, Geometry Balkan Press 2006.Öğe Radical anti-invariant lightlike submanifolds of semi-Riemannian product manifolds(2008) Kiliç E.; Şahin B.We introduce radical anti-invariant lightlike submanifolds of a semi Riemannian product manifold and give examples. After we obtain the conditions of integrability of distributions which are involved in the definition of radical anti-invariant lightlike submanifolds, we investigate the geometry of leaves of distributions. We also obtain the induced connection is a metric connection and a radical anti-invariant lightlike submanifold is a product manifold under certain conditions. Finally, we study totally umbilical radical anti-invariant lightlike submanifolds and observe that they are totally geodesic under a condition. © TÜBİTAK.Öğe Sharp inequalities involving the Ricci curvature for Riemannian submersions(University of Kragujevac, Faculty of Science, 2017) Gülbahar M.; Eken Meriç S.; Kiliç E.In this paper, we obtain sharp inequalities on Riemannian manifolds admitting a Riemannian submersion and give some characterizations using these inequalities. We improve Chen-Ricci inequality for Riemannian submersion and present some examples which satisfy this inequality.Öğe Some inequalities on screen homothetic lightlike hypersurfaces of a Lorentzian manifold(2013) Gülbahar M.; Kiliç E.; Keleş S.In this paper, we establish some inequalities involving k-Ricci curvature, k-scalar curvature, the screen scalar curvature on a screen homothetic lightlike hypersurface of a Lorentzian manifold. We compute Chen-Ricci inequality and Chen inequality on a screen homothetic lightlike hypersurface of a Lorentzian manifold. We give an optimal inequality involving the ?(n1,..., nk)-invariant and some characterizations (totally umbilicity, totally geodesicity, minimality, etc.) for lightlike hypersurfaces.Öğe Symmetric lightlike hypersurfaces of a para-sasakian space form(Universitatii Al.I.Cuza din Iasi, 2016) Acet B.E.; Perktaş S.Y.; Kiliç E.In this paper, we study semi-symmetric, Ricci semi-symmetric and semi-parallel lightlike hypersurfaces of a para-Sasakian space form. © 2016, Universitatii Al.I.Cuza din Iasi. All rights reserved.
