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Sign-preserving solutions for a class of asymptotically linear systems of second-order ordinary differential equations
Full text linkWe study multiplicity of solutions to an asymptotically linear Dirichlet problem associated with a planar system of second order ordinary differential equations. The existence of two sign-preserving component-wise solutions is guaranteed when the Morse indexes of the linearizations at zero and at infinity do not coincide, and one of the asymptotic problems has zero-index. The proof is developed in the framework of topological and shooting methods and it is based on a detailed analysis and characterization of the phase angles in a two-dimensional setting
Multiplicity of Radial Ground States for the Scalar Curvature Equation Without Reciprocal Symmetry
Full text linkWe study existence and multiplicity of positive ground states for the scalar curvature equation , x in R^n, when the function is bounded above and below by two positive constants, i.e. for every positive r, it is decreasing in (0,R) and increasing in for a certain positive constant R.
We recall that in this case ground states have to be radial, so the problem is reduced to an ODE and, then, to a dynamical system via Fowler transformation.
We provide a smallness non perturbative (i.e. computable) condition on the ratio which guarantees the existence of a large number of ground states with fast decay,
i.e. such that as , which are of bubble-tower type.
We emphasize that if K(r) has a unique critical point and it is a maximum the radial ground state with fast decay, if it exists, is uniqu
Multiplicity of ground states for the scalar curvature equation
Full text linkWe study existence and multiplicity of radial ground states for the scalar curvature equation Δu+K(|x|)un+2n-2=0,x∈Rn,n>2,when the function K: R+→ R+ is bounded above and below by two positive constants, i.e. 0 0 , it is decreasing in (0, 1) and increasing in (1 , + ∞). Chen and Lin (Commun Partial Differ Equ 24:785–799, 1999) had shown the existence of a large number of bubble tower solutions if K is a sufficiently small perturbation of a positive constant. Our main purpose is to improve such a result by considering a non-perturbative situation: we are able to prove multiplicity assuming that the ratio K ̄/K̲ is smaller than some computable values
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
Risultati di molteplicità per problemi ai limiti superlineari e asintoticamente lineari
No full textNo abstract availabl
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
Multiplicity of solutions for asymptotically linear n-th order boundary value problems
No full textIn this paper we investigate existence and multiplicity of solutions, with
prescribed nodal properties, to a two-point boundary value problem of
asymptotically linear -th order equations. The proof follows a shooting
approach and it is based on the weighted eigenvalue theory for linear -th
order boundary value problem
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
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