1,720,970 research outputs found
Neural Network Algorithms for Height Resolved Ozone Retrievals from OMI Level 1b Data
No full textOzone is one of the most important trace gases in the Earth's atmosphere. It is mainly present in the stratosphere, with only about 10% of the total column amount in the troposphere. Despite the relatively small ozone abundance, the solar radiation at wavelengths below 310 nm does not reach the Earth surface because of the large ozone absorption and Rayleigh scattering. Anthropogenic releases of ozone depleting substances play a dramatic role in a possible increase of the surface UV radiation. Human activity is very likely to be responsible also for an increase in tropospheric ozone caused by the photochemical production from industrial emission of ozone precursors such as carbon monoxide, volatile organic compounds, and nitrogen oxides. The effect of these variations at lower altitudes, with respect to background values, have been estimated to be the third largest source of the greenhouse effect. Monitoring ozone concentrations and trends, especially in highly polluted locations, is a relevant topic in recent geosciences research. Obtaining height resolved information of ozone from satellite platform is an exciting task. Difficulties stem e.g. from the weak sensitivity of the Earth’s radiances to variations of ozone at lower altitudes and from the relatively high horizontal resolution needed to resolve small scale features of regional air pollution, as well as for climatological issues. A daily global coverage may be required to continuously observe the air masses and check the air quality.
The Dutch-Finnish Ozone Monitoring Instrument (OMI) on board the NASA-Aura spacecraft matches these requirements by combining a satisfactory spatial resolution and a daily global coverage. From this point of view, the OMI can more satisfactorily provide useful data with respect to the Envisat SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) or the ERS-2 Global Ozone Monitoring Experiment (GOME). The OMI is an ESA third party mission.
Usually height resolved information about ozone is inferred from the satellite signal by means of Optimal Estimation (OE) inversion techniques. Recently, we proposed Neural Network (NN) based schemes to retrieve both ozone profiles and Tropospheric Ozone Column (TOC) from Earth’s radiance UV/VIS nadir measurements. NN algorithms are particularly suited to solve complex non-linear problems like the inversion of satellite radiance measurements for atmospheric profiles retrieval. NNs are expected to be less sensitive to calibration uncertainties than the OE, and to work more reliably in aerosols/cloudy scenarios. The networks were trained using both simulated and experimental data. The input wavelengths were selected following an RTM-NN extended pruning method to objectively exploit the information budget of the satellite measurements and the role of ultraviolet and visible radiation was investigated.
In this work we report on the potential of NNs in the retrieval of atmospheric ozone concentration from NASA-Aura OMI Level 1b data. The results obtained with two NNs, one for ozone pProfile retrievals and the second for a direct TOC retrievals, respectively, are shown and the different design issues addressed. Both data from ozone sondes and complementary satellite data, e.g. Aura Microwave Limb Sounder (MLS) measurements, are considered as the “true†outputs during the training phase. A comparison with operational OMI Level 2 tropospheric ozone and Level 2 ozone profiles products is also presented and the results are discussed. OMI, MLS and some correlative data were provided by the Aura Validation Data Center (AVDC)
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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