1,721,019 research outputs found
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
Gromov-Witten theory and spectral curve topological recursion
Full text linkGromov-Witten theory and spectral curve topological recursion are important parts of modern algebraic geometry and mathematical physics. In my thesis I study relations between these theories and some important new aspects and applications of them. In particular, a construction for a local spectral curve which produces the same invariants as a given Gromov-Witten theory is presented in the thesis, as well as constructions for quantum spectral curves for several important theories, and a new proof of the so-called ELSV formula
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
Moduli spaces of curves and enumerative geometry via topological recursion
Full text linkThe thesis considers several enumerative geometric problems concerning the topology of the moduli space of curves and their combinatorics. These enumerative geometric problems are analysed from different intertwined points of view and using different mathematical tools, including Hurwitz theory, Givental theory, cohomological field theories, integrable hierarchies, Fock spaces, quantum curves, and a relatively new powerful technique introduced by Chekhov, Eynard and Orantin known as topological recursion. These subjects lie in the interplay between enumerative algebraic geometry, differential geometry and mathematical physics
Systèmes intégrables, variétés de Frobenius et théories cohomologiques des champs
No full textDans cette thèse, nous étudions la géométrie sous-jacente des systèmes intégrables. Nous nous intéressons particulièrement aux hiérarchies d'EDPs d'évolution, tau-symétriques et bi-Hamiltoniennes.D'abord, nous explorons la relation étroite entre les champs des systèmes intégrables et la géométrie algébrique en donnant une nouvelle démonstration de la conjecture de Witten, qui construit la string tau-fonction de la hiérarchie de Korteweg-de Vries par théorie d'intersection des espaces de modules des courbes stables avec des points marqués. Cette nouvelle démonstration se base sur la géométrie des cycles de ramification double, des classes tautologiques dont le comportement sous des pullbacks des applications forgetful et gluing facilitent le calcul des nombres d'intersection des psi classes.Dans un deuxième temps, nous examinons la hiérarchie de Dubrovin et Zhang, un système intégrable construit en déformant la structure bi-Hamiltonienne de type hydrodynamique associée à une variété de Frobenius. Cette hiérarchie intégrable est Hamiltonienne et tau-symétrique, et est conjecturée bi-Hamiltonienne. Nous démontrons un théorème d'annulation des termes de degrés négatifs du deuxième crochet de Poisson qui fournit des preuves fortes pour soutenir cette conjecture. La démonstration de ce théorème illustre les implications que la récursivité bi-Hamiltonienne et les relations tautologiques en cohomologie des espaces de modules des courbes stables ont sur la structure bi-Hamiltonienne des hiérarchies de Dubrovin et Zhang.Dans un troisième temps, nous conjecturons une formule pour le plus simple des produits non triviaux des cycles de ramification double DR_g(1,1)lambda_g en termes des classes de cohomologie réprésentées par les strates standards. Malgré l'existence de formules qui mettent en relation des cycles de ramification double avec autres classes tautologiques plus naturelles, elles sont beaucoup plus compliquées que celle proposée ici. Cette conjecture précise dans le cas d'un point les relations tautologiques conjecturales de Buryak, Guéré et Rossi, qui sont équivalentes à l'existence d'une transformation de Miura qui relie la hiérarchie de ramification double de Buryak et celle de Dubrovin et Zhang.Finalement, nous analysons la géométrie différentielle des systèmes intégrables en (2 + 1) dimensions par variétés de Frobenius de dimension infinie. Plus concrètement, nous étudions, formèlement et analytiquement, l'équation de Dubrovin de la variété de Frobenius de la hiérarchie de Toda bidimensionnelle à sa singularité irrégulière. Le fait qu'elle est de dimension infinie implique un comportement qualitativement différent de celui de son analogue en dimension finie, la variété de Frobenius sous-jacente à la hiérarchie de Toda élargie. Les deux différences les plus rémarcables sont que les solutions formèles de l'équation de Dubrovin ne sont pas uniques et que les solutions analytiques ne forment pas un système complet. Conjointement ces deux caractéristiques compliquent l'analyse du phénomène de Stokes, que nous réalisons en divisant l'espace des solutions en une infinité des sous-espaces de dimension deux.In this dissertation, we study the underlying geometry of integrable systems, in particular tausymmetric bi-Hamiltonian hierarchies of evolutionary PDEs and differential-difference equations.First, we explore the close connection between the realms of integrable systems and algebraic geometry by giving a new proof of the Witten conjecture, which constructs the string taufunction of the Korteweg-de Vries hierarchy via intersection theory of the moduli spaces of stable curves with marked points. This novel proof is based on the geometry of double ramification cycles, tautological classes whose behavior under pullbacks of the forgetful and gluing maps facilitate the computation of intersection numbers of psi classes.Second, we examine the Dubrovin-Zhang hierarchy, an integrable system constructed from a Frobenius manifold by deforming its associated pencil of Poisson structures of hydrodynamic type. This integrable hierarchy was proved to be Hamiltonian and tau-symmetric, and conjectured to be bi-Hamiltonian. We prove a vanishing theorem for the negative degree terms of the second Poisson bracket, thus providing strong evidence to support this conjecture. The proof of this theorem demonstrates the implications the bi-Hamiltonian recursion relation and tautological relations in the cohomology rings of the moduli spaces of stable curves have on the bi-Hamiltonian structure of the Dubrovin-Zhang hierarchies.Third, we propose a conjectural formula for the simplest non-trivial product of doubleramification cycles DR_g(1,1)lambda_g in terms of cohomology classes represented by standard strata. Although there are known formulas relating double ramification cycles to other, more natural tautological classes, they are much more complicated than the one conjectured here. This conjecture refines the one point case of the Buryak-Guéré-Rossi conjectural tautological relations, which are equivalent to the existence of a Miura transformation relating Buryak's double ramification hierarchies and the Dubrovin-Zhang ones.Finally, we analyze the differential geometry of (2 + 1) integrable systems through infinitedimensional Frobenius manifolds. More concretely, we study, both formally and analytically, the Dubrovin equation of the 2D Toda Frobenius manifold at its irregular singularity. The fact that it is infinite-dimensional implies a qualitatively different behavior than its finite-dimensional analogue, the Frobenius manifold underlying the extended Toda hierarchy. The two most remarkable differences are non-uniqueness of formal solutions to the Dubrovin equation and non-completeness of the analytic ones. These features together greatly complicate the analysis of Stokes phenomenon, which we perform by splitting the space of solutions into infinitely many two-dimensional subspaces
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