1,720,965 research outputs found
Surgery on -manifolds with S\sp 1-actions
No full textWe study the topological structure of all 3-manifolds obtained by surgery along principal fibers of a closed orientable -manifold. As a consequence, we give alternative proofs of some classical results due to W. Heil and L. Moser. Moreover, we completely specify the Seifert invariants for the considered manifolds. Finally we classify the manifolds obtained by surgery along certain Seifert links and determine geometric presentations of their fundamental groups
On the effective Yang-Mills Lagrangian and its equation of motion
No full textThe path integral quantization of gauge theories leads to an effective Lagrangian denoted by L_eff. Its associated equation of motion is of the form d_A^* F_A + (1/2) J_A = 0, where J_A is the vacuum polarization current arising from propagation of quantum fields around the background field A. In this paper we will give a more detailed description of the current J_A
On the determination of PL-manifolds by handles of lower dimension
No full textWe extend the Montesinos theorem about handle presentations of PL 4-manifolds to dimension n. For this we consider closed PL (n + 1)-manifolds of the same homotopy type as X = #p (S^1 x S^n). Then we extend PL homeomorphisms of X over the solid handlebody
Four-manifolds with surface fundamental groups
No full textWe study the homotopy type of closed connected topological 4-manifolds whose fundamental group is that of an aspherical surface F. Then we use surgery theory to show that these manifolds are s-cobordant to connected sums of simply-connected manifolds with an S^2-bundle over F
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
A geometric study of Sieradski groups
No full textThis paper is devoted to the study of orientable closed 3-manifolds uniformized by cyclically presented groups, introduced by Sieradski in Invent. Math. 84 (1986) and by certain generalizations of them. It is shown that these manifolds are cyclic coverings of the 3-sphere branched over torus knots. This answers in the affirmative an open question suggested by the referee of the quoted paper and recovers the main theorem of a paper of R. Thomas published in Bull. Korean Math. Soc. 28 (1991)
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