1,721,258 research outputs found
Resonances and residue operators for pseudo-Riemannian hyperbolic spaces
Get PDFFor any pseudo-Riemannian hyperbolic space over
or , we show that the resolvent
of the Laplace-Beltrami operator
on can be extended meromorphically across the spectrum of as a
family of operators . Its poles are called
resonances and we determine them explicitly in all cases. For each resonance,
the image of the corresponding residue operator in forms a
representation of the isometry group of , which we identify with a
subrepresentation of a degenerate principal series. Our study includes in
particular the case of even functions on de Sitter and Anti-de Sitter spaces.
For Riemannian symmetric spaces analogous results were obtained by
Miatello-Will and Hilgert-Pasquale. The main qualitative differences between
the Riemannian and the non-Riemannian setting are that for non-Riemannian
spaces the resolvent can have poles of order two, it can have a pole at the
branching point of the covering to which extends, and the residue
representations can be infinite-dimensional.Comment: 23 pages, final published versio
Common but new: Bartramia rosamrosiae, a "new" widespread species of apple mosses (Bartramiales, Bryophytina) from the Mediterranean and western North America
No full textDamayanti, Lia, Muñoz, Jesús, Wicke, Susann, Symmank, Lars, Shaw, Blanka, Frahm, Jan-Peter, Quandt, Dietmar (2012): Common but new: Bartramia rosamrosiae, a "new" widespread species of apple mosses (Bartramiales, Bryophytina) from the Mediterranean and western North America. Phytotaxa 73 (1): 37-59, DOI: 10.11646/phytotaxa.73.1.6, URL: http://biotaxa.org/Phytotaxa/article/view/phytotaxa.73.1.
FIGURE 2. PCA diagrams for the first two factors, F1 and F2 in Common but new: Bartramia rosamrosiae, a "new" widespread species of apple mosses (Bartramiales, Bryophytina) from the Mediterranean and western North America
No full textFIGURE 2. PCA diagrams for the first two factors, F1 and F2, with the variance explained by each. Italicized numbers correspond to the characters in Table 1. A: Bartramia (Anacolia) laevisphaera; M: Bartramia rosamrosiae sp. nov.; S: Bartramia stricta.Published as part of Damayanti, Lia, Muñoz, Jesús, Wicke, Susann, Symmank, Lars, Shaw, Blanka, Frahm, Jan-Peter & Quandt, Dietmar, 2012, Common but new: Bartramia rosamrosiae, a "new" widespread species of apple mosses (Bartramiales, Bryophytina) from the Mediterranean and western North America, pp. 37-59 in Phytotaxa 73 (1) on page 44, DOI: 10.11646/phytotaxa.73.1.6, http://zenodo.org/record/506648
FIGURE 4 in Common but new: Bartramia rosamrosiae, a "new" widespread species of apple mosses (Bartramiales, Bryophytina) from the Mediterranean and western North America
No full textFIGURE 4. Comparison of: A. Bartramia laevisphaera. B. B. stricta. C. B. rosamrosiae sp. nov. First row: Sporophyte dry (scale bar 2 mm). Second row: Plant dry (scale bar 2 mm). Third row: Plant wet (scale bar 2 mm).Published as part of Damayanti, Lia, Muñoz, Jesús, Wicke, Susann, Symmank, Lars, Shaw, Blanka, Frahm, Jan-Peter & Quandt, Dietmar, 2012, Common but new: Bartramia rosamrosiae, a "new" widespread species of apple mosses (Bartramiales, Bryophytina) from the Mediterranean and western North America, pp. 37-59 in Phytotaxa 73 (1) on page 46, DOI: 10.11646/phytotaxa.73.1.6, http://zenodo.org/record/506648
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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