1,720,972 research outputs found
Oscillon collapse to black holes
Full text linkUsing numerical relativity simulations we study the dynamics of pseudo-topological objects called oscillons for a class of models inspired by axion-monodromy. Starting from free field solutions supported by gravitational attractions, we investigate the effect of adding self-interactions, and contrast this with the effect of adding self-interactions whilst removing gravitational support. We map out regions of the parameter space where the initial conditions rapidly collapse to black holes, and other regions where they remain pseudo-stable or disperse
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
Innovative technique for large septal perforation repair and radiological evaluation.
No full textPERFORATION OF THE NASAL SEPTUM MAY HAVE MULTIPLE CAUSES:
traumatic, iatrogenic, infectious, degenerative, overuse of vasoconstrictors, abuse of cocaine and more recently chemotherapy agents. Perforations are also classified according to their size and type of cartilaginous or osteocartilaginous deficit, as well as location (front, middle and rear). Many surgical techniques have been proposed to repair the perforation, although the results are often unsatisfactory for perforations of small and medium size; in large perforations permanent obliteration of the defect cannot always be ensured. It is often necessary to use tissues from inside the nasal turbinates or cartilage from other donor sites such as the ear or rib, and various techniques are discussed in light of the recent literature. The perforations observed in the last eight years and surgical approaches performed in open or closed approaches are taken into account. The authors propose a new technique that has been used with success in many types of septal perforation regardless of aetiology, and in particular large perforations, which allows for the use of the osteocartilaginous donor site as a hump. It is also useful in reductive rhinoseptoplasty, which targets selection to easily obtain mucopericondral flaps with an extramucosal technique and to obtain also an aesthetic improvement
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
Innovative technique for large septal perforation repair and radiological evaluation.
Full text linkPerforation of the nasal septum may have multiple causes: traumatic, iatrogenic, infectious, degenerative, overuse of vasoconstrictors,
abuse of cocaine and more recently chemotherapy agents. Perforations are also classified according to their size and type of cartilaginous
or osteocartilaginous deficit, as well as location (front, middle and rear). Many surgical techniques have been proposed to repair the perforation,
although the results are often unsatisfactory for perforations of small and medium size; in large perforations permanent obliteration
of the defect cannot always be ensured. It is often necessary to use tissues from inside the nasal turbinates or cartilage from other donor
sites such as the ear or rib, and various techniques are discussed in light of the recent literature. The perforations observed in the last eight
years and surgical approaches performed in open or closed approaches are taken into account. The authors propose a new technique that
has been used with success in many types of septal perforation regardless of aetiology, and in particular large perforations, which allows
for the use of the osteocartilaginous donor site as a hump. It is also useful in reductive rhinoseptoplasty, which targets selection to easily
obtain mucopericondral flaps with an extramucosal technique
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
De Sitter vs Quintessence in String Theory
Full text linkDe Sitter solutions have been recently conjectured to be incompatible with quantum gravity. In this paper we critically assess the progress and challenges of different mechanisms to obtain de Sitter vacua in string compactifications and compare them to quintessence models. We argue that, despite recent criticisms, de Sitter models reached a level of concreteness and calculational control which has been improving over time. On the other hand, building string models of quintessence appears to be more challenging and requires additional fine-tuning. We discuss the tension between the swampland conjecture and the Higgs potential and find examples which can evade fifth-force bounds even if they seem very hard to realise in string theory. We also comment on the tension with low-redshift data and explore ultra-light axions from string theory as dark energy candidates
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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