1,720,955 research outputs found
Identifizierung von Thalamusskernen auf orthogonalen Ebenen von strukturellen Magnetisierungstransfer-MRT-Daten
No full textMittels der T1- und T2-gewichteten
Magnetresonanztomographie (MRT) stellt sich der Thalamus mit
geringem intrinsischem Kontrast dar. Ziel dieser Dissertation ist
die Evaluation kontrastoptimierten Parameterkarten des
Magnetisierungstransfer-Kontrastes bei 3 Tesla Feldstärke für die
systematische Identifizierung der Kerne des Thalamus.
An 20 gesunden Probanden (23-31 Jahre) wurden nach einem zuvor
optimierten Protokoll mittels einer 3D Gradientenecho-Sequenz
(FLASH) Volumendaten mit T1-, Protonendichte- und MT-Wichtung
aufgenommen (3 Tesla Siemens Trio, sagittale Partitionen, 0,95 mm
isotrope Auflösung, 25 min Messzeit), und hieraus
MT-Parameterkarten berechnet. Die Auswertung erfolgte mit einem 3D
Visualisierungsprogramm nach Interpolation auf 0,5 mm in
Orientierung entlang der Interkommissurallinie. Die MT-Karten
zeigen einen hohen Kontrast zwischen myelinreichen und –armen
Strukturen. Faserreiche Strukturen stellen sich hyperintens dar,
zellkernreiche Strukturen hypointens und flüssigkeitsreiche
Strukturen stark hypointens. Die Benennung der Kerne folgte nach
der amerikanischen Nomenklatur von Jones.
Es konnten im Thalamus 25 der 34 Kerne der Jones-Klassifikation
eindeutig identifiziert werden, darüber hinaus auch andere
Strukturen wie die Substantia nigra und der Nucleus subthalamicus.
Als Leitstrukturen innerhalb des Thalamus dienen die Bahnen der
Lamina medullaris interna (engl. IML) und des Tractus
mamillothalamicus (engl. MTT). Diese ermöglicht eine Einteilung des
Thalamus in vier Gruppen: lateral und medial der IML, intralaminar
und in der Gabelung der IML. Einige Kerne lassen sich direkt
identifizieren. Weitere Kerne können aufgrund ihrer relativen Lage
zugeordnet werden.
Die verwendete MRT-Technik eröffnet somit innerhalb klinisch
anwendbarer Messzeiten erstmalig die Möglichkeit, die Mehrzahl der
Kerne des dorsalen Thalamus direkt, d.h. ohne Überlagerung von
stereotaktischen Atlanten, zu identifizieren.The human thalamus shows poor intrinsic
contrast on standard T1- and T2-weighted magnetic resonance images
(MRI). The aim of this thesis was to evaluate the use of contrast
optimized parameter maps of magnetization transfer (MT) contrast
for a systematic assignment of the thalamus nuclei at 3
Tesla.
20 healthy adults (23-31 years) were examined with a previously
optimized protocol of three-dimensional (3D) spoiled gradient-echo
MRI (FLASH). From three datasets at 0.95 isotropic resolution with
T1-, proton density- and MT-weighting (3 Tesla Siemens Trio,
sagittal partition, 25 min scanning time), parameter maps of MT
saturation were calculated. The data was interpolated at 0.5 mm in
the orientation of the intercommissural reference system and
visualized with 3D viewing software.
The MT maps provide the highest contrast between structures of high
axonal content (hyperintense), those containing predominantly
neuronal somata (hypointense) and high water content (more
hypointense). The delineation of the nuclei was based on the North
American nomenclature of Jones.
25 of the 34 nuclei in the classification of Jones were clearly
identified on the MT parameter maps, as well as other structures
such as the substantia nigra and the nucleus subthalamicus. The
major landmarks in the thalamus are the internal medullary lamina
(IML) and the mamillo-thalamic tract (MTT). They divide the nuclei
into four groups: lateral and medial of the IML, intralaminar and
enclosed by the IML. The nuclei are either directly identified or
they are assigned by their relative position. The applied MRT
technique provides for the first time in feasible clinical
measurement time a direct delineation of most nuclei of the dorsal
thalamus without superimposition of stereotactic atlases
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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