1,721,363 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
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
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
Martian atmospheric escape : MAVEN data Analysis
No full textDifférentes observations de l’atmosphère martienne font état de son échappement vers l’espace. Parmi les mécanismes d’échappement identifiés comme potentiellement à l’origine de cet échappement, le criblage atmosphérique est considéré comme un processus minoritaire de nos jours. Le taux d’échappement par criblage étant difficilement directement mesurable, les estimations actuelles reposent essentiellement sur l’utilisation de modèles analytiques ou numériques mais varient fortement d’un modèle à l’autre en raison de l’absence d’une mesure précise du flux de particules impactant l’atmosphère et à l’origine du criblage atmosphérique. Le but principal de ma thèse a été d’étudier les données obtenues par les instruments du satellite « Mars Atmosphere and Volatile EvolutioN » (MAVEN) pour mieux comprendre les mécanismes à l’origine des précipitations ioniques dans l’atmosphère martienne ainsi que leur dépendance en fonction des paramètres solaires (vent solaire et flux radiatif). Ainsi, j'ai pu étudier l'influence des évènements solaires sur les précipitations ioniques et en isoler les paramètres clefs : la pression dynamique et le champ électrique. J'ai ensuite réalisé la première étude établissant une dépendance anti-corrélée entre les précipitations d'ions et le flux EUV. J'ai ensuite étudié l'influence de la pression dynamique sur les précipitations d'ions en comparant les résultats d'observations de MAVEN aux résultats de simulations LatHyS.Various observations suggest that Mars permanently loses its atmosphere into space. Several mechanisms have been identified among which atmospheric sputtering is considered a minor process nowadays. A direct measurement of sputtering signature being not accessible with the actual instruments, most of the estimates of its present efficiency are based on analytical or numerical models. They all depend on an accurate knowledge of the ion flux and energy distribution precipitating into Mars’ atmosphere and at the origin of Mars’ atmospheric sputtering. flux. Constraining this precipitating ion flux is therefore a key information to better understand if Mars’ atmospheric sputtering could have been a significant mechanism of atmospheric escape into space. The main goal of my PhD has been to study the measurements obtained by the instruments of the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft to better understand the mechanisms at the origin of the ion precipitation into the Martian atmosphere as well as their dependence on the solar wind and radiation conditions. Thus, I was able to study the influence of solar events on ion precipitation and to isolate its key parameters: the dynamic pressure and the electric field. I then carried out the first study establishing an anti-correlated dependency between ion precipitation and EUV flux. I then studied the influence of dynamic pressure on ion precipitation by comparing the results of MAVEN observations with the results of LatHyS simulations
Modeling the jovian plasma interaction with Europa
No full textEurope, l'un des quatre satellites galiléens de Jupiter, fait l'objet d'une attention particulière de la communauté scientifique car il est susceptible d'abriter des conditions d'habitabilité favorables. La présence d'un océan d'eau liquide salée en sous-surface a été mise en évidence par l'analyse des observations de la sonde Galileo, combinée à des simulations numériques. Par ailleurs, des observations du télescope spatial Hubble et la réanalyse de données de la sonde Galileo, comparées à des simulations numériques ont renforcé l'hypothèse de la présence de panaches de vapeur d'eau. Traverser ces dernières pourrait permettre de comprendre la composition de l'océan sous-terrain.L'exploration des lunes galiléennes constitue l'un des principaux objectifs de la mission JUICE (JUpiter ICy moons Explorer) de l'ESA. En préparation des futures observations, un effort de modélisation a été entrepris pour caractériser le système magnétosphère de Jupiter-Europe. Pour caractériser l'interaction entre le plasma jovien, le champ magnétique et l'atmosphère d'Europe, j'ai utilisé le modèle LatHyS (LATMOS Hybrid Simulation). LatHyS est un modèle de simulation hybride 3D, multi-espèces et parallèle qui combine une description cinétique des ions avec une description fluide des électrons. Ce modèle de simulation nous permet de représenter la dynamique et la structure de l'environnement ionisé dans lequel baigne la lune.Mon travail a consisté à développer l'environnement d'Europe au sein de LatHyS. L'atmosphère et l'ionosphère en ont notamment été un aspect central. Les modèles d'interactions Europe-plasma jovien décrivent l'atmosphère de manière empirique et avec un modèle analytique. Cependant, j'ai mis en place une description issue d'un modèle d'exosphère planétaire 3D, appelé EGM, pour caractériser l'atmosphère d'Europe. En couplant EGM avec LatHyS, nous pouvons prendre en compte diverses espèces neutres majoritaires, intégrer des asymétries et obtenir une ionosphère plus proche de la réalité. En parallèle, j'ai développé une méthode d'optimisation qui permet de réduire la taille de l'environnement de la simulation, ce qui permet de réduire le temps d'exécution. Par la suite, j'ai réalisé de multiples simulations comparant diverses conditions neutres et ionosphériques (d'empirique à entièrement modélisées) avec des observations de Galileo afin d'étudier la réponse du système lors de ces variations. Puis j'ai analysé la réponse du plasma à un environnement théorique pendant les deux survols prévus d'Europe par JUICE. Pour finir, j'ai travaillé sur un programme qui calcule la propagation d'une onde radio dans un environnement magnétique. C'est un travail préliminaire qui a pour but d'intégrer l'environnement simulé par le modèle LatHyS dans ce code de tracé de rayon afin d'étudier la propagation des ondes radio émises par Jupiter lors d'une occultation observée par la sonde JUICE.Europe, one of Jupiter's four Galilean moons, is subject of recent interest from the scientific community due to its potential to host favorable habitable conditions. The presence of a subsurface salty liquid water ocean has been confirmed through the analysis of Galileo probe observations, combined with numerical simulations. Additionally, observations from the Hubble Space Telescope and a reanalysis of Galileo probe data, compared to numerical simulations, have strengthened the hypothesis of the existence of water vapor plumes. Passing through these plumes could provide insights into the composition of the underground ocean.Exploring the Galilean moons is one of the primary objectives of the ESA's JUpiter ICy moons Explorer (JUICE) mission. In preparation for future observations, modeling efforts have been undertaken to characterize the system jovian magnetosphere-Europa. To characterize the interaction between the jovian plasma, the magnetic field, and Europa's atmosphere, I used the LatHyS (LATMOS Hybrid Simulation) model. LatHyS is a 3D, multi-species, parallel hybrid simulation model that combines a kinetic description of ions with a fluid description of electrons. This simulation model allows us to represent the dynamics and structure of the ionized environment surrounding the moon.My work focused on developing Europa's environment within LatHyS, with a particular emphasis on the atmosphere and ionosphere. Models of the interaction between Europa and Jupiter's plasma traditionally describe the atmosphere empirically and with an analytical model. However, I implemented a description based on a 3D planetary exosphere model called EGM to characterize Europa's atmosphere. By coupling EGM with LatHyS, we can account for various major neutral species, incorporate asymmetries, and obtain an ionosphere that is closer to reality. In parallel, I developed a simulation optimization method to reduce the size of the simulation environment, which reduces runtime. Subsequently, I conducted multiple simulations comparing various neutral and ionospheric conditions (from empirical to fully modeled) with Galileo observations to study the system's response to these variations. I also analyzed the plasma's response to a theoretical environment during the two planned flybys of Europa by JUICE. Finally, I worked on a program that calculates the propagation of a radio wave in a magnetic environment. This preliminary work aims to integrate the environment simulated by the LatHyS model into this ray tracing code to study the propagation of radio waves emitted by Jupiter during an occultation observed by JUICE
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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