1,721,008 research outputs found
Suspending The Cartan Embedding Of ℍpn Through Spindles And Generators Of Homotopy Groups
No full textWe provide an equivariant suspension of the Cartan embedding of the symmetric space S4n+3 → ℍPn {right arrow, hooked} Sp(n+1); this construction furnishes geometric generators of the homotopy group of π4n+6Sp(n + 1). We study the topology and geometry of the image of this generator; in particular we show that it is a spindle, minimal with respect to the biinvariant metric from Sp(n + 1). This spindle also admits a different metric of positive curvature away from the cone singular point. © 2011 Springer Basel AG.601255263Abresch, U., Durán, C.E., Püttmann, T., Rigas, A., Wiedersehen metrics and exotic involutions of Euclidean spheres (2007) J. Reine Angew. Math., 605, pp. 1-21Abresch, U., Durán, C.E., Püttmann, T., Rigas, A., An Exotic Involution of the 5-sphere, Quicktime Movie, , http://homepage.ruhr-uni-bochum.de/Thomas.Puettmann/XInvolution.htmlBalinskaya, I.S., Minimal cones of the adjoint action of classical Lie groups (1986) Russ. Math. Surv., 41, pp. 201-202Bott, R., The stable homotopy of the classical groups (1959) Ann. Math. (2), 70, pp. 313-337Bryant, R., Personal CommunicationDurán, C.E., Pointed Wiedersehen metrics on exotic spheres and diffeomorphisms of S6 (2001) Geom. Dedic., 88 (1-3), pp. 199-210Durán, C.E., Rigas, A., Equivariant homotopy and deformations of diffeomorphisms (2009) Differ. Geom. Appl., 27 (2), pp. 206-211Durán, C.E., Mendoza, A., Rigas, A., Blakers-Massey elements and exotic diffeomorphisms of S6 and S14 (2004) Trans. Am. Math. Soc., 356 (12), pp. 5025-5043Fomenko, A.T., (1990) Variational Principles in Topology, Mathematics and Its Applications, Vol. 42, , Dordrecht: KluwerGorodski, C., Enlarging totally geodesic submanifolds of symmetric spaces to minimal submanifolds of one dimension higher (2004) Proc. Am. Math. Soc., 132, pp. 2441-2447Gromoll, D., Meyer, W., An exotic sphere with non-negative sectional curvature (1972) Ann. Math., 96 (2), pp. 413-443Helgason, S., (1978) Differential Geometry, Lie Groups, and Symmetric Spaces, , New York: Academic Press Inc. [Harcourt Brace Jovanovich Publishers]Hsiang, W.-Y., Lawson, H.B., Minimal submanifolds of low cohomogeneity (1971) J. Diff. Geom., 5, pp. 1-38Quast, P., Spindles' in symmetric spaces (2006) J. Math. Soc. Japan, 58 (4), pp. 985-994Püttmann, T., (2004) Some Homotopy Groups of the Classical Groups From a Geometric Viewpoint, , Habilitation thesis, BochumPüttmann, T., Rigas, A., Presentations of the first homotopy groups of the unitary groups (2003) Comment. Math. Helv., 78 (3), pp. 648-662Rigas, A., Geodesic spheres as generators of πq(O), πq+1(BO) (1978) J. Diff. Geom., 13 (4), pp. 527-545Toda, H., (1962) Composition Methods in the Homotopy Groups of Spheres. Annals of Mathematics Studies, Vol. 49, , Princeton: Princeton University Pres
The long term X-ray time lags of NGC 4051
No full textWe present the long term, frequency-dependent, X-ray time lags of the Seyfert galaxy NGC 4051. We used Rossi X-ray Timing Explorer(RXTE) light curves in the 2–4, 4–7, and 7–10 keV bands and we measured the time lags at 10−7–10−6 Hz. This is the lowest frequency range that active galactic nuclei time lags have ever been measured. The variations in the higher energy bands are delayed with respect to the variations we observe at 2–4 keV, in agreement with the time lags at high frequencies. When we combine our results with those from the model fitting of the time lags at higher frequencies we find that that the X-ray hard lags in NGC 4051 follow a power law of slope ∼−1 over a broad frequency range, from ∼10−7 to ∼10−3 Hz. This is consistent with the time lags of Cyg X–1, a result which further supports the analogy between active galaxies and Galactic X-ray black hole binaries
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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