836 research outputs found

    Classification of topological symmetry groups of KnK_n

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    In this paper we complete the classification of topological symmetry groups for complete graphs KnK_n by characterizing which KnK_n can have a cyclic group, a dihedral group, or a subgroup of Dm×DmD_m \times D_m where mm is odd, as its topological symmetry group.Comment: 19 pages; v2 lists authors correctly on arXiv; v3 substantially revises the introductio

    Aufgaben und Verantwortlichkeiten von IT-Nutzern anhand von COBIT

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    Als wesentliche Beteiligte am IT-Management (bzw. Informationsmanagement) werden für gewöhnlich die Unternehmensleitung, die Fachabteilung und die IT-Abteilung genannt. Demgemäß konzentriert sich die Diskussion um die Verantwortung für die effektive und effiziente Nutzung der informationellen Ressourcen eines Unternehmens auf die Aufgabenteilung und die daraus resultierende Verantwortung dieser drei Gruppen. IT-Nutzer in der Fachabteilung stellen in dieser Diskussion regelmäßig keine eigenständige Gruppe keine, sondern fungieren lediglich als Adressat der IT-Abteilung. Das Ziel des Arbeitspapiers besteht darin, anhand des Referenzwerkes COBIT aufzuzeigen, welche Aufgaben und Verantwortlichkeiten IT-Nutzern in der Fachabteilung prinzipiell übertragen werden können.COBIT ; Control-Objectives ; Informationsmanagement ; Informations- und Kommunikationstechnologien ; IT-Governance ; ITNutzer ; IT-Prozes

    Optical Spin Noise of a Single Hole Spin Localized in an (InGa)As Quantum Dot

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    We advance spin noise spectroscopy to the ultimate limit of single spin detection. This technique enables the measurement of the spin dynamic of a single heavy hole localized in a flat (InGa)As quantum dot. Magnetic field and light intensity dependent studies reveal even at low magnetic fields a strong magnetic field dependence of the longitudinal heavy hole spin relaxation time with an extremely long T1T_1 of \ge 180 μ\mus at 31 mT and 5 K. The wavelength dependence of the spin noise power discloses for finite light intensities an inhomogeneous single quantum dot spin noise spectrum which is explained by charge fluctuations in the direct neighborhood of the quantum dot. The charge fluctuations are corroborated by the distinct intensity dependence of the effective spin relaxation rate

    Asymptotic Spectrum of Kerr Black Holes in the Small Angular Momentum Limit

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    We study analytically the highly damped quasinormal modes of Kerr black holes in the small angular momentum limit. To check the previous analytic calculations in the literature, which use a combination of radial and tortoise coordinates, we reproduce all the results using the radial coordinate only. According to the earlier calculations, the real part of the highly damped quasinormal mode frequency of Kerr black holes approaches zero in the limit where the angular momentum goes to zero. This result is not consistent with the Schwarzschild limit where the real part of the highly damped quasinormal mode frequency is equal to c^3 ln(3)/(8 pi G M). In this paper, our calculations suggest that the highly damped quasinormal modes of Kerr black holes in the zero angular momentum limit make a continuous transition from the Kerr value to the Schwarzschild value. We explore the nature of this transition using a combination of analytical and numerical techniques. Finally, we calculate the highly damped quasinormal modes of the extremal case in which the topology of Stokes/anti-Stokes lines takes a different form.Comment: 13 pages, 6 figure

    Computer assisted analysis of auroral images obtained from high altitude polar satellites

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    Automatic techniques that allow the extraction of physically significant parameters from auroral images were developed. This allows the processing of a much larger number of images than is currently possible with manual techniques. Our techniques were applied to diverse auroral image datasets. These results were made available to geophysicists at NASA and at universities in the form of a software system that performs the analysis. After some feedback from users, an upgraded system was transferred to NASA and to two universities. The feasibility of user-trained search and retrieval of large amounts of data using our automatically derived parameter indices was demonstrated. Techniques based on classification and regression trees (CART) were developed and applied to broaden the types of images to which the automated search and retrieval may be applied. Our techniques were tested with DE-1 auroral images

    Reinduction of Bevacizumab in Combination with Pegylated Liposomal Doxorubicin in a Patient with Recurrent Glioblastoma Multiforme Who Progressed on Bevacizumab/Irinotecan

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    Glioblastoma multiforme (GBM) carries a dismal prognosis despite the current standard of multimodality treatments. Recent studies showed promising results to a regimen consisting of a VEGF inhibitor, (bevacizumab) and a topoisomerase I inhibitor (irinotecan) [BI] in recurrent GBM. However, those patients with GBM who progress on BI will succumb to their disease generally in a very short period of time. We report a case of a 56-year-old male patient with GBM who declined surgical resection and received chemoradiation with temozolomide. This treatment was withheld secondary to significant thrombocytopenia. Subsequently, he achieved stable disease for 10 months with a regimen consisting of thalidomide and tamoxifen before progressing. This was followed by bevacizumab with irinotecan [BI], for which he had a significant partial response for 8 months with subsequent progression. Reinducing the patient with bevacizumab in combination with a pegylated liposomal doxorubicin [PLD] (a topoisomerase II inhibitor) demonstrated antitumor activity with significant shrinkage of contrast enhancing mass and peritumoral edema
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