1,721,066 research outputs found
On the geometry of quantum mechanics
No full textWe will present a short review of some work we have done in the last ten years with Giuseppe Marmo, on the attempt to formulate some interesting physical problems — such as the Quantum Inverse Problem, Alternative Structures and Berry Phase — in a geometrical setting
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
A bibliometric study of scientific literature on the dietary therapies for epilepsy in Scopus
No full textObjectives: The aim of this study was to provide a descriptive overview of the impact and production of
literature on dietary therapies for epilepsy and perform a citation analysis of the related research articles.
Methods: We searched for ‘ketogenic OR low-glycemic OR medium chain OR modified Atkins in TITLE AND
epilep*’ in Title/Abstract/Keyword in Scopus database.
Results: A total of 661 references were retrieved, 80% had been published after 2000s, 87% were published
in English, and 39% of the publications were published in nine journals. The majority (76.3%) of research
articles describe the clinical application of the dietary therapies regarding the classical ketogenic diet
(80%), followed by the modified Atkins diet (11.5%), medium chain triglyceride diet (6.4%), and low
glycemic index treatment (2.0%); the remaining are basic science studies on the mechanisms of action.
The citation analysis revealed that the latter have the highest percentage variation in citation per
publication across the years. Concerning the article cohorts, the greatest number of citations per
publication was in 1998.
Discussion: The overview of the literature on the dietary therapy of epilepsy evidences a growing interest in
the field with a striking prevalence of clinical over basic science studies. The most cited clinical studies have
validated the efficacy of the dietary therapies; the few studies on the mechanisms of action received a great
number of citations. Bibliometric analysis measuring the trends and the impact of the scientific literature
would help researchers to a best knowledge of this specific topic
An introduction to the Hubbard model
No full textIn these notes we review some of the basic features of the 2D Hubbard model, thought of as the appropriate model for the description of the Cu - O planes in the cuprate superconductors. We discuss briefly the weak-coupling regime of the model and, in the opposite limit, the mapping of the one band Hubbard model onto an AFM Heisenberg model at half filling and onto the t - J model below half filling. We discuss next Emery's three band model and its mapping onto the so-called "spin-fermion" model. Its continuum limit is discussed by making use of an adiabatic followed by a gradient expansion. We review briefly how the model maps onto a nonlinear sigma model and some of the features of the latter
On the resistance offered to compressible flow by obstructions in series
No full textA method is proposed for the determination of the flow characteristic of two flow restrictions in series, where an eliptical curve represents the relationship between the expansion coefficient (ratio of upstream and downstream pressures) and the reduced flow rate' for each individual obstruction. Elipse parameters are calculated for choking flow conditions of the combined system and the accuracy of the method is considered in the light of the assumptions made. (C.C.B.
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
La radice delle virtù: l'umiltà medievale tra discorso metaforico e disscussioni scolastiche
No full textL'umiltà, virtù specificamente cristiana assente dai sistemi morali del mondo antico gode per tutto l'altro Medioevo di una situazione di assoluto privilegio. Particolarmente apprezzata dal mondo monastico, essa rappresenta il fondamento e la radice di tutte le virtù, come illustra l'immagine dell'albero delle virtù particolarmente diffusa nel XII secolo. Spetta ai teologi scolastici (soprattutto Bonaventura da Bagnoregio e Tommaso d'Aquino) ridefinire il ruolo dell'umiltà nel quadro di un'etica rinnovata che deve misurarsi col sistema delle virtù aristoteliche riscoperte nell'Etica Nicomachea
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
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