1,720,968 research outputs found
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
Μαύρες οπές και σκουληκότρυπες στα πλαίσια γενικευμένων θεωριών βαρύτητας με βαθμωτά πεδία και ανώτερους βαρυτικούς όρους
Full text linkIn this Ph.D. dissertation we study the emergence of black-hole and wormhole solutions in theframework of the Einstein-scalar-Gauss-Bonnet (EsGB) theory. Particularly we study a family oftheories where the coupling function f(φ) between the scalar field of the theory and the quadraticGauss-Bonnet gravitational term has an arbitrary form. At first, we analytically derive that theaforementioned family of theories may evade the constraints imposed by Bekenstein's No-Scalar Hair theorems and new solutions for black holes may be found. Then, using numerical integration methods we find solutions for black holes for many different forms of the coupling function. Also, we derive their physical characteristics namely their mass, scalar charge, horizon area and entropy as well.Subsequently, by introducing a cosmological constant in the theory we investigate the existence ofnovel black-hole solutions. Specifically, assuming that the cosmological constant may be positive ornegative we find numerical solutions which are asymptotically de Sitter or anti-de Sitter. In addition, as in the case of the asymptotically flat black holes, for each case we derive their physical characteristics. Finally, in the framework of the EsGB theory we derive novel wormhole solutions. The Gauss-Bonnet wormholes are traversable, may have a single or a double throat and do not demand the existence of exotic matter.Στην παρούσα Διδακτορική Διατριβή μελετάμε λύσεις Μαύρων Οπών και Σκουληκότρυπων στα πλαίσια της Γενικευμένης Θεωρίας Βαρύτητας Einstein-Scalar-Gauss-Bonnet (EsGB). Ειδικότερα μελετούμε μια οικογένεια θεωριών όπου η συνάρτηση σύζευξης f(\f) ανάμεσα στο βαθμωτό πεδίο της θεωρίας και τον τετραγωνικό βαρυτικό όρο Gauss-Bonnet έχει εν γένει μια γενική μορφή. Αρχικά αποδεικνύουμε αναλυτικά ότι η οικογένεια αυτή των θεωριών δεν υπόκειται στους περιορισμούς που υποβάλουν τα No-Scalar Hair theorems του Bekenstein και νέες λύσεις ασυμπτωτικά επίπεδων μαύρων οπών μπορούν να βρεθούν. Στη συνέχεια, χρησιμοποιώντας μεθόδους αριθμητικής ολοκλήρωσης, προσδιορίζουμε νέες λύσεις μαύρων οπών (επιλέγοντας κάθε φορά συγκεκριμένη μορφή για τη συνάρτηση σύζευξης). Επιπλέον εξάγουμε τα χαρακτηριστικά τους, δηλαδή την μάζα τους, το βαθμωτό τους φορτίο, την επιφάνεια και την εντροπία τους. Έπειτα, εισάγοντας μια κοσμολογική σταθερά στην θεωρία ερευνούμε εκ νέου την ύπαρξη λύσεων μαύρων οπών. Συγκεκριμένα θεωρώντας πως η κοσμολογική σταθερά μπορεί να είναι θετική ή αρνητική βρίσκουμε αριθμητικές λύσεις οι οποίες είναι ασυμπτωτικά de Sitter ή anti-de Sitter αντίστοιχα. Επιπλέον όπως και στην περίπτωση των ασυμπτωτικά επίπεδων λύσεων, σε κάθε περίπτωση προσδιορίζουμε και ταχαρακτηριστικά των νέων αυτών λύσεων μαύρων οπών. Τέλος, στα πλαίσια της EsGB θεωρίαςβρίσκουμε λύσεις που περιγράφουν σκουληκότρυπες. Οι Gauss-Bonnet σκουληκότρυπες είναιδιασχίσιμες, μπορούν να έχουν μονό ή διπλό λαιμό και δεν απαιτούν την ύπαρξη εξωτικής ύλης σεκανένα σημείο του χωροχρόνου.207 σ
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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