1,720,987 research outputs found
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
Interaction effects in spin-valve structures
No full textMost applications in electronics are based on manipulation of the electron charge. Currently, there is also a lot of research into the possibility to make use of the electron spin, for example in magnetoelectronics. This field of research studies hybrid systems consisting of ferromagnetic metals, paramagnetic metals and insulators. In this thesis we present a theoretical description of a number of physical structures whose operation is based on the spin-valve principle. A spin valve consists of two ferromagnetic elements with a non-magnetic material in between. The electrical resistance of a spin valve can be varied by changing the angle between the magnetization directions of the two ferromagnets. We are especially interested in effects of the interaction between electrons on electronic transport in spin-valve structures. As the experimentally studied structures are getting smaller, interactions play an increasingly important role.Applied Science
Studio di un progetto di miglioramento della qualità assistenziale in ambito penitenziario
No full textVariations 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
Quantum Ratchets
No full textIn this thesis, ratchet systems operating in the quantum regime are investigated. Ratchet systems, also known as Brownian motors, are periodic systems presenting an intrinsic asymmetry which can be exploited to extract work out of unbiased forces. As a model for ratchet systems, we consider the motion of a particle in a one-dimensional periodic and asymmetric potential, interacting with a thermal environment, and subject to an unbiased driving force. In quantum ratchets, intrinsic quantum fluctuations as well as the tunnel effect enrich the transport mechanisms. The investigation of quantum ratchets allows one to gain fundamental understanding on the dynamics of quantum dissipative systems. Starting from a continuous ratchet potential and applying a path integral formalism, we develop two approaches, beyond a semiclassical description, where the dynamics can be mapped onto that of an effective tight-binding model. In the first approach, a parameter regime is chosen such that only few low energy quantum states in each well of the periodic potential are involved in the dynamics of the particle. The second approach leads to a duality relation between the original system and a single-band tight-binding model. The two methods are valid in different regimes of parameters, the second one including the classical limit. We get an analytical expression for the stationary velocity of the particle, which shows reversals as a function of the driving force and of the temperature. The second method allows us to extract the explicit dependence of the velocity on the parameters of the potential, and thus to characterize the potentials which lead to the highest rectification efficiency. We also discuss the connection between this theoretical model and measurements of the dynamics of vortices in quasi one-dimensional Josephson junction arrays.Applied Science
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
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
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