1,721,000 research outputs found
On a non-homogeneous and non-linear heat equation
No full textWe consider the Cauchy-problem for a parabolic equation of the
following type:
where , n >2, is supercritical. We supplement this equation by the initial
condition , and we allow to be either bounded or
unbounded in the origin but smaller than stationary singular
solutions. We discuss local existence and long time behaviour for
the solutions for a wide class of non-homogeneous
non-linearities . We show that in the supercritical case, ground
states with slow decay lie on the threshold between
initial data corresponding to blow-up solutions, and the basin of attraction of the null solution. Our
results extend previous ones in that we allow to be a Matukuma-type potential and in that we allow
it to depend on in a more general way.
We explore such a threshold in the subcritical case
too, and we obtain a result which is new even for the model case .
We find a family of initial data
which have fast decay (i.e. ), are
arbitrarily small in - norm, but which correspond to blow-up solutions
Global well-posedness of the two-dimensional horizontally filtered simplified Bardina turbulence model on a strip-like region
Get PDFWe consider the 2D simplified Bardina turbulence model, with horizontal filtering, in an unbounded strip-like domain. We prove global existence and uniqueness of weak solutions in a suitable class of anisotropic weighted Sobolev spaces
On the existence of an inertial manifold for a deconvolution model of the 2D mean Boussinesq equations
No full textStability of ground states for a nonlinear parabolic equation
Get PDFWe consider the Cauchy-problem for the parabolic equation
where , , and is either critical or
supercritical with respect to the Joseph-Lundgren exponent.
In particular, we improve and generalize some known results concerning
stability and weak asymptotic stability of positive ground states
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
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