1,720,962 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
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
Optical pumping in rubidium-87 — Linear polarization on the (F g = 2 ↔ F e = 2) transition in the D2 line
No full textResource for calculations of optical pumping, following the methodology described in Eur. J. Phys. 38, 045703 (2017). The project contains explicit evolution matrices for different problems (that is, different configurations, atoms .....), explicit equations for the time evolutions, mathematica codes, plotted results, and more. Itis done in a way that the project can gradually be expanded, with more and more atoms, more and more specific problems, and so on.We present results of a method for calculating optical pumping rates in 87 Rb, as described in [1]. We use linearly polarized light on the (F g = 2 ↔ F e = 2) transition to populate an angular momentum state in the F g = 2 hyperfine structure level of the ground state, with magnetic quantum number M g = 0 — that is a clock state. The open decay path to F g = 1 necessitates repumping light, and this is accordingly included in the calculation. The method is shown to function well for the studied system. Absolute scale level populations as functions of time, detunings, intensities and starting parameters are derived
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
Optical pumping in rubidium-87 — Impure polarization (a mixture of σ + , σ − and π light) on the (F g = 2 ↔ F e = 3) transition in the D2 line
No full textResource for calculations of optical pumping, following the methodology described in Eur. J. Phys. 38, 045703 (2017). The project contains explicit evolution matrices for different problems (that is, different configurations, atoms .....), explicit equations for the time evolutions, mathematica codes, plotted results, and more. Itis done in a way that the project can gradually be expanded, with more and more atoms, more and more specific problems, and so on.We present results of a method for calculating optical pumping rates in 87 Rb, as described in [1]. We use light with an impure polarization (i.e. a mixture of σ + , σ − and π light) to populate a stretched angular momentum state in the F g = 2 hyperfine structure level of the ground state. The method is shown to function well for the studied system. Absolute scale level populations as functions of time, detuning, intensity, relative intensity of polarizations, and starting parameters are derived
Simplified approach for quantitative calculations of optical pumping
No full textInternational audienceWe present a simple and pedagogical method for quickly calculating optical pumping processes based on linearised population rate equations. The method can easily be implemented on mathematical software run on modest personal computers, and can be generalized to any number of concrete situations. We also show that the method is still simple with realistic experimental complications taken into account, such as high level degeneracy, impure light polarization, and an added external magnetic field. The method and the associated mathematical toolbox should be of value in advanced physics teaching, and can also facilitate the preparation of research tasks
Optical pumping in rubidium-87 — A mixture of σ + and σ − circularly polarized light on the (F g = 1 ↔ F e = 0) transition in the D2-line
No full textResource for calculations of optical pumping, following the methodology described in Eur. J. Phys. 38, 045703 (2017). The project contains explicit evolution matrices for different problems (that is, different configurations, atoms .....), explicit equations for the time evolutions, mathematica codes, plotted results, and more. Itis done in a way that the project can gradually be expanded, with more and more atoms, more and more specific problems, and so on.We present results of a method for calculating optical pumping rates in 87 Rb, as described in [1]. We use a mixture of circularly polarised light (σ + and σ −) on the (F g = 1 ↔ F e = 0) transition to populate an angular momentum state in the F g = 1 hyperfine structure level of the ground state, with magnetic quantum number M g = 0 — that is a clock state. The method is shown to function well for the studied system. Explicit analytical equations for all level populations as functions of time, detuning, intensity, relative intensities of the polarization, and starting parameters are derived
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
- …
