1,721,012 research outputs found
Thermal magnetoresistance from magnon scattering from a domain wall in an antiferromagnetic insulator
No full textWe theoretically investigate magnon heat transport in an antiferromagnetic (AFM) insulator containing a domain wall (DW) in the presence of a magnetic field applied along the easy axis. We show that the intrinsic spin of the DW couples to the external magnetic field, which modifies the transmission of spin wave through the DW. Applying the magnetic field lifts the degeneracy between two AFM magnon modes and results in different occupation numbers for the two magnon modes. Combined with the finite reflection of a narrow domain wall, this is found to have a significant impact on the magnon heat transport, giving rise to thermal magnetoresistance. Our findings suggest that an AFM DW can be used as a controllable element for regulating the magnon heat current in magnonic devices through the application of a magnetic field.
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
Gauge invariance and Ward identities in nonlinear response theory
No full textWe present a formal analysis of nonlinear response functions in terms of correlation functions in real- and imaginary-time domains. In particular, we show that causal nonlinear response functions, expressed in terms of nested commutators in real time, can be obtained from the analytic continuation of time-ordered response functions, which are more easily amenable to diagrammatic calculation. This generalizes the well-known result of linear response theory. We then use gauge invariance arguments to derive exact relations between second-order response functions in density and current channels. These identities, which are non-perturbative in the strength of inter-particle interactions, allow us to establish exact connections between nonlinear optics calculations done in different electromagnetic gauges
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
The beautiful invisible: creativity, imagination, and theoretical physics
No full textChallenging the image of theoretical physics as a dry discipline, The Beautiful Invisible shows that this highly abstract science is in fact teeming with beautiful concepts, and the task of imagining them demands profound creativity, just as creative as the work of poets or magical realist novelists such as Borges and Musil. "A good scientific theory is like a symbolic tale, an allegory of reality," writes Giovanni Vignale, as he uncovers the unexpected links between theoretical physics and artistic creativity. In engaging and at times poetic prose, and with ample quotations from many of the writers he admires, Vignale presents his own unorthodox accounts of fundamental theoretical concepts such as Newtonian mechanics, superconductivity, and Einstein's theory of relativity, illuminating their profound implications. Throughout, the author treats readers to glimpses of physics as "exercised in the still night, when only the moon rages." Indeed, as we delve behind now-familiar concepts such as "electron spin" and "black hole," the world that we take for granted melts away, leaving a glimpse of something much stranger
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
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