407 research outputs found
On one class of holonomy groups in pseudo-Riemannian geometry
We describe a new class of holonomy groups on pseudo-Riemannian manifolds.
Namely, we prove the following theorem. Let g be a nondegenerate bilinear form
on a vector space V, and L:V -> V a g-symmetric operator. Then the identity
component of the centraliser of L in SO(g) is a holonomy group for a suitable
Levi-Civita connection.Comment: (revised version
Realisation of holonomy algebras on pseudo-Riemannian manifolds by means of Manakov operators
In the present thesis we construct a new class of holonomy algebras in pseudo-Riemannian
geometry. Starting from a smooth connected manifold M, we consider its (1;1)-tensor
fields acting on the tangent spaces. We then prove that there exists a class of pseudo-
Riemannian metrics g on M such that the (1;1)-tensor fields are g-self adjoint and their
centralisers in the Lie algebra so(g) are holonomy algebras for the Levi-Civita connection
of g. Our construction is elaborated with the aid of Manakov operators and holds for any
signature of the metric g
Liquid-based cytology and its practicability in Bulgaria
PURPOSE: Our aim was to summarize the foreign and our own experience in screening the cervical cancer by using conventional Papanicolaou (PAP) smear and liquid-based cytology (LBC).MATERIAL AND METHODS: In the Department of Obstetrics and Gynecology, Medical University of Varna, we examined 100 patients and compared the results from LBC with those from conventional PAP smear concerning different criteria as well as to test LBC practicability in Bulgaria.RESULTS: There were significant advantages of LBC mainly due to the lower number of unsatisfactory results and higher specificity of low-grade squamous intraepithelial lesions (LSIL). The comparison with the results from foreign studies demonstrated the same tendencies and diagnostic values.CONCLUSION: Our investigation proved the benefits of LBC in screening the cervical cancer. A much broader application of this method in Bulgaria was recommended taking into consideration that it was rarely used at presence.Scripta Scientifica Medica 2013; 45(2): 66-69
Using web scraping for real estate price analysis
In the present paper, a survey is being made of the areas, in which the use of Web scraping is necessary for adaptation to dynamic changes, demanding processing and generalizing of large volume of data from different web sources. An exemplary implementation for Web scraping is presented for price analysis of the real estate market. The technology that gives possibility of integration of the intended activities in development of the application has been reviewed. The overall procedure in the researching, development and realization of the proposed application can be used as a good practice in adaptation of the knowledge and skills of the graduating students for the requirements, dynamics and organization of the work in a software company as well as for the professional co-operation between the academic lecturers and representatives of the software business
On a new class of holonomy groups in pseudo-Riemannian geometry
On a new class of holonomy groups in pseudo-Riemannian geometr
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