1,720,953 research outputs found
Effect of the new iterative reconstruction technique "Iterative Model Reconstruction" (IMR) on the visibility of normal and abnormal lung structures in low dose chest CTs in comparison to iDose4TM and the conventional filtered back projection (FBP)
No full textIn dieser Arbeit wurde der neuartige iterative Bildrekonstruktionsalgorithmus „Iterative Model Reconstruction“ (IMR) hinsichtlich seines Einflusses auf Bildrauschen, Bildeindruck sowie Abgrenzbarkeit normaler und pathologischer Lungenstrukturen in Niedrigdosis-CTs der Lunge untersucht und mit dem Vorgängermodell iDose4TM und der herkömmlichen gefilterten Rückprojektion (FBP) verglichen. Die Rohdatensätze von 81 computertomographischen Untersuchungen des Thorax wurden mit FBP sowie verschiedenen Iterationsstufen von iDose4TM und IMR rekonstruiert. Die mittlere effektive Dosis der Niedrigdosis CT Untersuchungen betrug 0,86 ± 0,2 mSv. Für die objektive Analyse wurden in allen Rekonstruktionen Messungen der Rausch- und Dichtewerte durchgeführt. Zwei Radiologen, die über 7- und 12-jährige klinische Erfahrung in der Beurteilung von Lungen-CT-Untersuchungen verfügen, bewerteten alle Rekonstruktionen unabhängig voneinander hinsichtlich der subjektiven Bildqualität anhand einer 5-Punkte-Skala. Zusätzlich wurde die Abgrenzbarkeit normaler Strukturen (1. große Bronchien und Gefäße, 2. kleine Bronchien, Bronchiolen und kleine Gefäße, 3. pleurale und subpleurale Strukturen, 4. interlobuläre Septen, 5. intralobuläres Interstitium) und pathologischer Strukturen (1. retikuläre Zeichnung, 2. kleine Rundherde, 3. Areale mit reduzierter Lungendichte 4. Areale mit erhöhter Lungendichte) untersucht. Unsere Ergebnisse konnten zeigen, dass IMR das Bildrauschen um bis zu 88% gegenüber FBP und um bis zu 72% im Vergleich zu iDose4TM reduziert (p<0,001). Hinsichtlich des Einflusses von IMR für die Bildqualität muss zwischen anatomischen und pathologischen Strukturen differenziert werden. Die Abgrenzbarkeit kleiner anatomischer Strukturen ist in den IMR-Rekonstruktionen den iDose4TM-Rekonstruktionen unterlegen. Im Gegensatz dazu war die Abgrenzbarkeit pathologischer Lungengenveränderungen in den IMR-Rekonstruktionen den FBP und iDose4TM -Rekonstruktionen überlegen. Lediglich die retikuläre Zeichnungsvermehrung ist in den iDose-Rekonstruktionen besser als in IMR darzustellen. Ursächlich für die schlechtere Bewertung der IMR-Rekonstruktionen hinsichtlich der kleineren anatomischen Strukturen sind ein weichgezeichneter Bildeindruck, eine zunehmende Unschärfe und die Reduktion des räumlichen Auflösungsvermögens. Diese nehmen mit zunehmender IMR-Iterationsstufe zu und können die diagnostische Sicherheit einschränken. Aufgrund dieser heterogenen Ergebnisse ist IMR in seiner jetzigen Fassung nicht das bevorzugte Bildrekonstruktionsverfahren von Niedrigdosis-CT-Untersuchung des Thorax. Dem gegenüber lieferte iDose4TM mit der Iterationsstufe L6 sowohl ein niedriges Bildrauschen als auch eine befriedigende Bildqualität und ermöglichte so die suffiziente Abgrenzbarkeit von sowohl anatomischen als auch pathologischen Lungenstrukturen. Das iterative Bildrekonstruktionsverfahren iDose4TM stellt eine geeignete Methode zur Rekonstruktion von Niedrigdosis-CT-Untersuchungen des Thorax dar und sollte in dir klinischen Routine etabliert werden.In this study we analysed the impact of the new iterative reconstruction technique Iterative Model Reconstruction (IMR, Philips Healthcare) on the subjective image quality of low dose chest CTs and compared it with the iDose4TM and Filtered Back Projection (FBP). Therefore we saved the raw data of 81 submillisievert chest CT studies (Brilliance iCT, Philips Healthcare), which are carried out during the clinical assessment and being reconstructed with FBP and multiple iteration levels of iDose4TM and IMR. The effective dose (E) was 0,86 ± 0,2 mSV. For the objective analysis we measured the parameters attenuation and objective image noise (OIN) in all reconstructed images. In addition, we compiled clinical data and dose information of the patients included in this study. For the subjective Analysis we assessed the effect of these diverse techniques on the image quality using a 5-Point-Scale, in order to objectify this subjective impressions. Two radiologists, with 7 and 12 years of clinical experience with chest CT, rated the visualisation of normal structures (1: intralobular interstitium, 2: interlobular septa, 3: small bronchi, bronchioles and vessels, 4: pleural and subpleural structures, 5: large bronchi and vessels) and abnormal structures (1: decreased lung attenuation, 2: increased lung attenuation, 3: reticular pattern, 4: small nodules) in all reconstructed images. They were blinded regarding the reconstruction techniques. Our results show that IMR is capable in reducing image noise up to 88 % compared to FBP. In comparison to iDose4TM the results show a noise reduction up to 72 % (p<0,001). Regarding the results of the subjective image quality and visualisation we have to differentiate between normal and abnormal findings. IMR is inferior compared to iDose4TM when it comes to normal structures. Nevertheless, it shows a superior performance in the graphic representation of abnormal structures apart from the reticular pattern. Its visualisation showed the best results using iDoseL6-reconstructions. The reasons for the poor rating of IMR compared to iDoseL6-reconstructions in visualisation of normal findings are a blotchy appearance and a loss of anatomical details, which result in a compromised diagnostic confidence. These negative effects increased with higher iteration levels of IMR. The iDose4TM-reconstructions showed a range of satisfying up to good results in normal, aswell as in abnormal findings
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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