1,720,968 research outputs found
Double wells: Nevanlinna analyticity, distributional borel sum and asymptotics
No full textWe consider the energy levels of a Stark family, in the parameter j, of quartic double wells with perturbation parameter g: H(g, j) = p(2) + x(2)(1 - gx)(2) - j (gx - 1/2). For non-even j (and for the symmetric case j = 0) we prove analyticity in the full Nevanlinna disk Rg(-2) > R(-1) of the g(2)-plane, as predicted by Crutchfield. By means of an approximation we give a heuristic estimate of the asymptotic small g behaviour, showing the relation between the avoided crossings and the failure of the usual perturbation series
Absence of geometrical phases in the rotating stark effect
Full text linkWe prove that there are no geometrical phases in a one electron atom under a constant slowly varying rotating electric fiel
Dal blog all’opera letteraria. I diari online di Giuseppe Caliceti e Giulio Mozzi
Full text linkL’intervento si focalizza sui blog personali diffusi su internet a cavallo tra XX e XXI secolo, subito dopo l’accesso di massa alla Rete e appena prima dell’avvento dei social network. Si riflette, in particolar modo, su ciò che avviene in termini artistici e di autorialità quando dal blog viene ricavata un’opera letteraria: anzitutto dal punto di vista teorico, collocando i blog nel più vasto processo definito come «democratizzazione della letteratura»; poi dal punto di vista metodologico, riflettendo sulle difficoltà filologiche e pratiche che simili studi possono incontrare; infine attraverso l’analisi di due casi particolari – Giuseppe Caliceti e Giulio Mozzi – molto diversi tra loro, ma proprio per questo rappresentativi di due modi complementari di declinare gli stessi problemi
Analyticity and asymptotics for the Stark-Wannier states
No full textIt is proved that the Stark-Wannier states, as functions of the electric field, are analytic in a disc tangential to the real axis at the origin, with asymptotic expansion to the second order which coincides with the Wannier approximation up to the first order
Construction of PT-Asymmetric non-Hermitian Hamiltonians with CPT Symmetry
No full textWithin CPT-symmetric quantum mechanics the most elementary differential form of the charge operator C is assumed. A closed-form integrability of the related coupled differential self-consistency conditions and a natural embedding of the Hamiltonians in a supersymmetric scheme is achieved. For a particular choice of the interactions the rigorous mathematical consistency of the construction is scrutinized suggesting that quantum systems with non-self-adjoint Hamiltonians may admit probabilistic interpretation even in presence of a manifest breakdown of both T symmetry (i.e., Hermiticity) and PT symmetry
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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