1,721,039 research outputs found
Two particle spectrum of tensor multiplets coupled to AdS3×S3 gravity
No full textWe study certain infinite families of two-particle operators exchanged in 4pt correlators ⟨Op1Op2Op3Op4⟩ of tensor multiplets living on the AdS3×S3 background. This is the weakly curved, weakly coupled SUGRA theory dual to the D1-D5 system with RR flux. At tree level in Mellin space, all these correlators are nicely determined by a single amplitude, which makes manifest the large p limit, the connection with the flat space S-matrix, and a six dimensional conformal symmetry. We compute the (1,1)ׯ¯¯¯¯¯¯¯¯(1,1) superconformal blocks for the two-dimensional N=(4,4) conformal theory at the boundary, and then we obtain a formula for the anomalous dimensions of the two-particle operators exchanged in the symmetric and antisymmetric flavor channels. These anomalous dimensions solve a mixing problem which is analogous to the one in AdS5×S5 with interesting modifications. Along the way we show how the (1,1)ׯ¯¯¯¯¯¯¯¯(1,1) superconformal blocks relate to those in N=4 SYM in four dimensions, and provide new intuition on the known data for AdS5×S5.</p
NUOVE CONOSCENZE SULLA STRATIGRAFIA E DISTRIBUZIONE DEI DEPOSITI IGNIMBRITICI QUATERNARI NEL SOTTOSUOLO DELLA PIANA DEL SARNO ( SALERNO-CAMPANIA). ITALIA MERIDIONALE
No full textIL RUOLO DEI DEPOSITI PIROCLASTICI NELL'ANALISI CRONOSTRATIGRAFICA DEI TERRENI QUATERNARI DEL SOTTOSUOLO DELLA PIANA CAMPANA (ITALIA MERIDIONALE).
No full textN=2 supersymmetric field theories on 3-manifolds with A-type boundaries
Full text linkGeneral half-BPS A-type boundary conditions are formulated for N = 2 supersymmetric field theories on compact 3-manifolds with boundary. We observe that under suitable conditions manifolds of the real A-type admitting two complex supersymmetries (related by charge conjugation) possess, besides a contact structure, a natural integrable toric foliation. A boundary, or a general co-dimension-1 defect, can be inserted along any leaf of this preferred foliation to produce manifolds with boundary that have the topology of a solid torus. We show that supersymmetric field theories on such manifolds can be endowed with half-BPS A-type boundary conditions. We specify the natural curved space generalization of the A-type projection of bulk supersymmetries and analyze the resulting A-type boundary conditions in generic 3d non-linear sigma models and YM/CS-matter theories
Double-trace spectrum of N=4 supersymmetric Yang-Mills theory at strong coupling
Full text linkThe spectrum of IIB supergravity on AdS5×S5 contains a number of bound states described by long double-trace multiplets in N=4 super Yang-Mills theory at large 't Hooft coupling. At large N these states are degenerate and to obtain their anomalous dimensions as expansions in 1N2 one has to solve a mixing problem. We conjecture a formula for the leading anomalous dimensions of all long double-trace operators which exhibits a large residual degeneracy whose structure we describe. Our formula can be related to conformal Casimir operators which arise in the structure of leading discontinuities of supergravity loop corrections to four-point correlators of half-BPS operators.</p
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
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