1,721,002 research outputs found
Validation of the IPSL Venus general circulation model with Venus Express data
Full text linkSeveral numerical models devoted to the simulation of Venus atmosphere have been developed. These models are useful instruments in the understanding of the mechanisms behind the observational features. However, before using their outputs to drive any conclusion about the dynamics and the structure of the atmosphere of Venus, we need to validate them. The process of validation passes by a comparison of the modelled and observational features. Among these numerical models, the Institut Pierre Simon Laplace (IPSL) Venus GCM is the one with a more physical approach, being capable to solve the radiative transfer for each layer of the simulated atmosphere. Our study makes use of Venus Express data – in particular VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) and VeRa (Venus Express Radio Science Experiment) observations – in order to validate this model. This work will analyze the temperature and wind fields in the atmosphere of Venus between 50 and 90 km, that is the range covered by observations. In this range – covering from the upper troposphere to the upper mesosphere – two different regimes are found in the observational thermal field, above and below ~ 76 km, with temperatures increasing towards the pole and towards the equator, respectively. At cloud top level (~ 68 km), permanent cold features, the cold collars, encircle the warmer poles. Winds velocities reach their maximum values (~ 120 m/s) at cloud top, but are faster than the solid body through the entire range of altitudes, determining a condition called superrotation. Seasonal thermal tides are negligible in data, but those related to the diurnal cycle, are present and have a large impact, especially in the upper atmosphere. Venus modelling has always suffered from the strong dependence of the simulation by the initial conditions and the different dynamical cores. Winds far weaker than observed, as well as the inability to reproduce the complex polar vortexes and the subpolar cold regions, have been the major issues for all the numerical simulations for Venus. However, to simulate the fast rotation of the atmosphere and to properly model the thermal structure associated to the polar and subpolar regions, means to understand the physical conditions under which these characteristics develop. Thus, the first objective of our validation of the IPSL Venus GCM is to estimate the general characteristics of the modelled atmosphere and their resemblance of observations. A first, qualitative comparison, is fundamental in recognizing the main dynamical regions in Venus atmosphere. Being the main goal of this work, the validation of a model through its comparison with the thermal and winds field in observational data, we need to clarify the adopted ingredients and the state of the art of our knowledge of Venus. Thus, in chapter 1 we present the overall characteristics of Venus atmosphere, in terms of its composition, thermal structure and dynamics. In chapter 2 we discuss the Venus Express mission, with a focus on the VIRTIS and VeRa experiments and the datasets that we used in this analysis. In chapter 3 we describe the evolution and the present state of the major numerical models trying to simulate the atmosphere of Venus, with a particular emphasis on the IPSL Venus GCM. Chapter 4 and chapter 5 present our validation: the former concerns the analysis of the average temperature and wind fields, the latter is about the thermal tides affecting the temperature and wind fields. As a result, we recognize the capability of the model to reproduce the main observational feature and we propose future steps in order to overcome the major discrepancies that we found in our validation
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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