1,720,973 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
Variations 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
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
Skyrmions magnétiques dans des multicouches : contrôle de leur nucléation et déplacement induits par courant électrique
No full textLes skyrmions magnétiques sont des textures de spin stabilisées grâce à l'interaction Dzyaloshinskii-Moriya. Cette interaction chirale favorise un enroulement particulier de l'aimantation et leur confère des propriétés intéressantes. Ils se comportent par exemple comme des particules et possèdent une topologie différente de l'état d'aimantation uniforme. Depuis les premières observations en 2011, les skyrmions ont fait l'objet d'études approfondies en raison de leur potentiel pour des applications futures, telles que la "racetrack memory". Cette thèse se concentre sur les skyrmions Néel, un type particulier de skyrmions, qui peuvent être stabilisés dans des multicouches magnétiques. En commençant par l'étude des différentes interactions magnétiques, il a été possible de définir des épaisseurs critiques qui régissent leur formation et de proposer un empilement optimisé pour les observer expérimentalement. Nous avons ensuite étudié leur nucléation, induite par impulsions de courant électrique dans divers dispositifs, par exemple grâce à l'insertion de constrictions sur les bords des pistes. Le cas des skyrmions dans des multicouches formant un antiferromagnétique synthétique, soit deux skyrmions de polarité opposée couplés ensemble, est également abordé par le biais d'une ingénierie des différentes épaisseurs des matériaux conduisant à leur stabilisation dans des multicouches à anisotropie variable. Dans le but de les intégrer dans des technologies futures, leur dynamique induite par courant électrique a aussi été étudiée avec l'optimisation des couples de spin afin d'améliorer leur mobilité. Cette étude a conduit à des systèmes dans lesquels les skyrmions sont plus rapides que les parois de domaine, ce qui est intéressant dans le but d'explorer comment ces deux objets interagissent l'un avec l'autre. Ce résultat est notamment attribué à la présence d'un fort couple field-like. Enfin, la question de leur fiabilité est abordée avec l'observation de leur déplacement sur plusieurs dizaines de micromètres et avec une discussion sur l'utilisation des mécanismes de répulsions skyrmion-skyrmion et skyrmion-paroi (de domaines) pour améliorer leur dynamique. Le déplacement des skyrmions le long de domaines magnétiques ouvre notamment de nouvelles possibilités concernant le contrôle de leur trajectoire et pourrait conduire à de nouvelles perspectives concernant les dispositifs visant à utiliser les skyrmions pour faire des portes logiques.Magnetic skyrmions are localized spin textures which stabilize thanks to the Dzyaloshinskii-Moriya interaction. This chiral interaction promotes a twisting of the magnetization, which grants skyrmions interesting properties. For example, they behave as particles and are topologically different from the uniform magnetization state. Since their first observations in 2011, skyrmions have been extensively studied because of their promise for future applications e.g. racetrack memory, neuromorphic computer, etc. This thesis is focused on Néel skyrmions, a peculiar type of skyrmions, which can be stabilized in various magnetic multilayers. Starting from the investigation of the different magnetic interactions present in such systems, it has been possible to define critical thicknesses which governs the formation of chiral textures and to propose optimized stacking to investigate experimentally their nucleation in thin films. This analysis is followed by their current induced formation in patterned devices, an important milestone for the potential applications mentioned before. As an example, through the insertion of notches at the edges of devices, a deterministic control of the nucleation events is achieved. The case of antiferromagnetic skyrmions, which are basically two skyrmions with opposite polarity coupled together, is also addressed through an engineering of the different materials thicknesses leading to their stabilization in multilayers with varying anisotropies along the vertical axis. With the goal to implement them in actual technologies, their current induced dynamics have been investigated through an optimization of the spin orbit torques, to enhance the skyrmion's mobility, for example through the use of Pt (below the magnetic layer) and Ta (above the magnetic layer). This study also leads to systems in which skyrmions are faster than domain walls, which is interesting to explore how both textures interact one with the other. This result is attributed to the presence of an unexpected Rashba mechanism at the Co|Al interface, which increases the field like component of the torque and slows down the domain walls. Finally, the question of their reliability is discussed with observations of their motion on tens of micrometres distances and with a presentation of the use of skyrmion-skyrmion and skyrmion-domains repulsions to improve their dynamics. This last result, the motion of skyrmions along magnetic domains, opens new possibilities concerning the control of their trajectory and could lead to new prospects for skyrmion logic devices
Skyrmions magnétiques dans des multicouches : contrôle de leur nucléation et déplacement induits par courant électrique
No full textMagnetic skyrmions are localized spin textures which stabilize thanks to the Dzyaloshinskii-Moriya interaction. This chiral interaction promotes a twisting of the magnetization, which grants skyrmions interesting properties. For example, they behave as particles and are topologically different from the uniform magnetization state. Since their first observations in 2011, skyrmions have been extensively studied because of their promise for future applications e.g. racetrack memory, neuromorphic computer, etc. This thesis is focused on Néel skyrmions, a peculiar type of skyrmions, which can be stabilized in various magnetic multilayers. Starting from the investigation of the different magnetic interactions present in such systems, it has been possible to define critical thicknesses which governs the formation of chiral textures and to propose optimized stacking to investigate experimentally their nucleation in thin films. This analysis is followed by their current induced formation in patterned devices, an important milestone for the potential applications mentioned before. As an example, through the insertion of notches at the edges of devices, a deterministic control of the nucleation events is achieved. The case of antiferromagnetic skyrmions, which are basically two skyrmions with opposite polarity coupled together, is also addressed through an engineering of the different materials thicknesses leading to their stabilization in multilayers with varying anisotropies along the vertical axis. With the goal to implement them in actual technologies, their current induced dynamics have been investigated through an optimization of the spin orbit torques, to enhance the skyrmion's mobility, for example through the use of Pt (below the magnetic layer) and Ta (above the magnetic layer). This study also leads to systems in which skyrmions are faster than domain walls, which is interesting to explore how both textures interact one with the other. This result is attributed to the presence of an unexpected Rashba mechanism at the Co|Al interface, which increases the field like component of the torque and slows down the domain walls. Finally, the question of their reliability is discussed with observations of their motion on tens of micrometres distances and with a presentation of the use of skyrmion-skyrmion and skyrmion-domains repulsions to improve their dynamics. This last result, the motion of skyrmions along magnetic domains, opens new possibilities concerning the control of their trajectory and could lead to new prospects for skyrmion logic devices.Les skyrmions magnétiques sont des textures de spin stabilisées grâce à l'interaction Dzyaloshinskii-Moriya. Cette interaction chirale favorise un enroulement particulier de l'aimantation et leur confère des propriétés intéressantes. Ils se comportent par exemple comme des particules et possèdent une topologie différente de l'état d'aimantation uniforme. Depuis les premières observations en 2011, les skyrmions ont fait l'objet d'études approfondies en raison de leur potentiel pour des applications futures, telles que la "racetrack memory". Cette thèse se concentre sur les skyrmions Néel, un type particulier de skyrmions, qui peuvent être stabilisés dans des multicouches magnétiques. En commençant par l'étude des différentes interactions magnétiques, il a été possible de définir des épaisseurs critiques qui régissent leur formation et de proposer un empilement optimisé pour les observer expérimentalement. Nous avons ensuite étudié leur nucléation, induite par impulsions de courant électrique dans divers dispositifs, par exemple grâce à l'insertion de constrictions sur les bords des pistes. Le cas des skyrmions dans des multicouches formant un antiferromagnétique synthétique, soit deux skyrmions de polarité opposée couplés ensemble, est également abordé par le biais d'une ingénierie des différentes épaisseurs des matériaux conduisant à leur stabilisation dans des multicouches à anisotropie variable. Dans le but de les intégrer dans des technologies futures, leur dynamique induite par courant électrique a aussi été étudiée avec l'optimisation des couples de spin afin d'améliorer leur mobilité. Cette étude a conduit à des systèmes dans lesquels les skyrmions sont plus rapides que les parois de domaine, ce qui est intéressant dans le but d'explorer comment ces deux objets interagissent l'un avec l'autre. Ce résultat est notamment attribué à la présence d'un fort couple field-like. Enfin, la question de leur fiabilité est abordée avec l'observation de leur déplacement sur plusieurs dizaines de micromètres et avec une discussion sur l'utilisation des mécanismes de répulsions skyrmion-skyrmion et skyrmion-paroi (de domaines) pour améliorer leur dynamique. Le déplacement des skyrmions le long de domaines magnétiques ouvre notamment de nouvelles possibilités concernant le contrôle de leur trajectoire et pourrait conduire à de nouvelles perspectives concernant les dispositifs visant à utiliser les skyrmions pour faire des portes logiques
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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