1,720,962 research outputs found
Min-max levels transition in parametrized elliptic problems on unbounded domains
No full textWe discuss some attempts to apply the classical variational methods, in the spirit of Ambrosetti-Rabinowitz, to parametrized elliptic problems defined on unbounded domains. We construct some min-max classes and establish some estimates which allow, for instance, to conclude that, while for a generic coefficient there is always a solution for all small values of the parameter, in the case of a coefficient with a suitable exponential decay and in dimension N = 2 the set of the values of the parameter for which the problem has a nontrivial solution is unbounded
Infinitely many positive solutions to some nonsymmetric scalar field equations: the planar case
No full textWe show the existence of infinitely many positive solutions u ∈ H1(R2) to the
equation −Delta u + a(x)u = u^p, with p > 1 , without asking, on the positive potential a(x),
any symmetry assumption as inWei and Yan (Calc Var Partial Differ Equ 37, 423–439, 2010)
or Devillanova and Solimini (Adv Nonlinear Studies 12, 173–186, 2012) or small oscillation
assumption as in Cerami et al. (Commun Pure Appl Math, doi:10.1002/cpa.21410, 2012)
6 and in Weiwei and Wei (Infinitely many positive solutions for Nonlinear equations with
non-symmetric Potential, 2012)
A multiplicity result for elliptic equations at critical growth in low dimension
No full textWe consider the problem -Deltau = \u\(2*-2)u + lambdau in Omega, u = 0 on partial derivativeOmega, where Omega is an open regular subset of R-N (N greater than or equal to 3), 2* = 2N/N - 2 is the critical Sobolev exponent and lambda is a constant in]0, lambda(1)[ where lambda(1) is the first eigenvalue of -Delta. In this paper we show that, when N greater than or equal to 4, the problem has at least N/2 + 1 (pairs of) solutions, improving a result obtained in [4] for N greater than or equal to 6
A variant on Miranda-Talenti estimate
Full text linkIn this note we prove formula (1.1),which extends to functions in W 2,2 with zero normal derivative the analogous formula (1.2) by G. Talenti ([5]) on functions with zero trace. To prove (1.1) we use the technique introduced by C. Miranda in [3] and give a geometrical interpretation of his results (formula (2.17))
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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