1,720,968 research outputs found
The silence of the little strings
No full textWe study the hydrodynamics of the high-energy phase of Little String Theory. The poles of the retarded two-point function of the stress energy tensor contain information about the speed of sound and the kinetic coefficients, such as shear and bulk viscosity. We compute this two-point function in the dual string theory and analytically continue it to lorentzian signature. We perform an independent check of our results by the lorentzian supergravity calculation in the background of non-extremal NS5-branes. The speed of sound vanishes at the Hagedorn temperature. The ratio of shear viscosity to entropy density is equal to the universal value 1/4? and does not receive ?' corrections. The ratio of bulk viscosity to entropy density equals 1/10?. We also compute the R-charge diffusion constant. In addition to the hydrodynamic singularities, the correlators have an infinite series of finite-gap poles, and a massless pole with zero attenuation
Complexity of Holographic Flavours and causality in QFTs with Gauss-Bonnet dual
No full textThis thesis is the compilation of two different projects undertaken during my PhD programme.
Chapter 2 covers the work on quantum complexity. Quantum complexity of a thermofield double state in a strongly coupled quantum field theory has been argued to be holographically related to the action evaluated on the Wheeler-DeWitt patch. The growth rate of quantum complexity in systems dual to Einstein-Hilbert gravity saturates a bound which follows from the Heisenberg uncertainty principle. This work, considers corrections to the growth rate in models with flavor degrees of freedom. These are realized by adding a small number of flavor branes to the system.
Holographically, such corrections come from the DBI action of the flavor branes evaluated on the Wheeler-DeWitt patch. After relating corrections to the growth of quantum complexity to corrections to the mass of the system, it is observed that the bound on the growth rate is never violated.
Chapter 3 covers the still ongoing project of causality in RG flows of systems with a Gauss-Bonnet gravity holographic dual. In order for the dual field theory to have no causality problems the speed of gravitons near the boundary of AdS must be bounded above by the speed of light. This bound is checked along the RG flow for QFTs that have AdS Gauss-Bonnet spacetime duals. It is found that, for certain values of the Gauss-Bonnet parameter, the field theory becomes acausal when sufficiently far away from the UV
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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