1,721,006 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
Abbildung mit dem Testaufbau für das INTEGRAL-Spektrometer SPI
No full textThe European Space Agency's INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) was launched on October 17, 2002. It carries two gamma-ray telescopes, the imager IBIS and the spectrometer SPI, together with X-ray and optical monitors. The spectrometer SPI is capable of measuring 20 keV - 8 MeV photons with an energy resolution of 2.3 keV at 1.3 MeV using 19 high-purity Germanium detectors. A tungsten-alloy coded aperture provides spatial information with an angular resolution of ~2.5° and a 16° fully coded field of view. In order to investigate the imaging properties of SPI in more detail than was possible during the flight instrument calibration - which had to fit in the tight satellite integration schedule -, I designed and built the SPI Imaging Test Setup (SPITS) at the Max-Planck-Institute for extraterrestrial Physics. SPITS consists of a coded aperture and two Ge detectors. The coded mask is based on a SPI mask development model, has the same Tungsten-alloy HURA mask coding as SPI, and is made of SPI flight model materials. The two hexagonal Ge detectors in their Al capsules, taken from the SPI flight instrument manufacturing line, are housed in a common vacuum cap. Mounted on an XY-table, they can be moved to cover the 19 SPI Ge detector positions. Data from 11 XY-table positions are combined to one SPITS measurement of 19 Ge spectra. This approach is feasible in a laboratory environment using radioactive sources since neither source activity nor background vary significantly during one measurement. SPITS was exposed to three types of sources: Laboratory point-like calibration sources with strong lines from 60 keV to 1836 keV, an extended source of 511 keV emission built from an 88Y source and a lead disk, and proton-irradiated accelerator targets emitting photons up to 9 MeV. All sources were placed 9 m from the SPITS detection plane. The laboratory point source measurements covered many incident directions not included in the SPI imaging calibrations, noteably seven incident directions which could be combined to the smaller of the standard SPI dithering patterns and a series of measurements that allowed the synthetization of dithered observations of two sources separated by 0.5°, 1.0°, 1.5°, etc. Neither a hexagonal dither pattern nor a dithered observation of sources separated by less than 1° can be synthesized from the SPI calibration data. In addition, the imaging of extended emission and an imaging observation of emission above 3 MeV have not been attempted with SPI during the instrument calibration. To obtain the image of the "sky" from a deconvolution of the measured line counts in the 19 Ge detectors, the instrument response to photons from all possible incident directions must be known. The required Instrument Response Functions (IRFs) for SPITS with sources at 9 m distance have been generated using the ray-tracing coded aperture modelling platform CAPTIF. I discuss the CAPTIF mass model and compare it to a GEANT mass model and measured properties of both SPI and SPITS components. A comparison of IRF-predicted with SPITS-measured detector count rates for two incident directions and several photon energies shows that, after introducing a correction factor, IRF and measurement generally agree to within 2 sigma. Both standard SPI image reconstruction algorithms, spiskymax and spiros, have been used to analyze the SPITS data. spiskymax, developed primarily for imaging extended emission, uses entropy maximization to determine the flux distribution. spiros ("SPI iterative removal of sources") is primarily geared towards point sources. In a cross-correlation image of the sky, the (remaining) brightest source is located and subsequently removed in dataspace; this process is repeated until all significant sources are found. Since there is no easy and clear stopping criterion for maximum entropy analysis, I studied the performance of spiskymax with simulated datasets to determine the best number of iterations for the SPITS point source analysis as a function of source intensity. The capability of the SPITS instrument to locate a point source depends strongly on the significance of the source and on the method of observation used ("staring" or "dithering"), as expected, and slightly on the source's angular distance from the instrument axis. For the observation of laboratory point sources, spiskymax and spiros location accuracies are routinely better than 10' even in non-dithered observations. Using both spiskymax and spiros, I find a correlation of the reconstructed positions with the spatial sky grid on which the IRFs were calculated. By adding spectra obtained with a source at different positions, observations of two sources could be synthesized. From these, the capability of the imaging system (instrument, IRFs, and analysis software) to disentangle and correctly locate two close sources can be determined. Of course, this capability again depends on the significance of the sources. For non-dithered observations, spiros source localizations are not reliable (roughly correct locations in far fewer than 80% of the cases), and the two brightest local maxima in the spiskymax image are often more than 0.2° away from their true positions even for angular separations of 2°. With dithering, results improve dramatically: all spiros and almost all spiskymax reconstructions of sources separated by 1° or more result in both sources being localized to better than 0.2°. With dithering, for example, spiros location accuracies in the case of two 22Na sources are better than 8' for source separations of 1° and better than 5' for larger separation angles. spiskymax reconstructions of the proton-irradiated targets in their respective gamma-ray lines also yielded reasonable results for non-dithered observations of one and two sources - the 19F target, for example, is positioned to better than 0.1° in several lines and for several different target positions. With spiros, however, the targets can often not be reasonably reconstructed from the same datasets. This is most likely due to the variability of "source activity" which makes the later combination of measurements at the 11 SPITS XY-table positions to one observation problematic. That these problems appear only with spiros might be an indication that it is more sensitive to discrepancies between the IRFs and the true instrument response than spiskymax. The fluxes of the laboratory sources are reconstructed to within the combined statistical and systematic error bars by both spiskymax and spiros. The largest contribution to the overall error stems from the IRF and IRF correction factor uncertainties, followed by the uncertainty of the source activity. Source fluxes are underestimated more often than overestimated. This fits both with the tendency of IRF-predicted count rates to overpredict measured photopeak counts and with a property of the spiskymax algorithm seen in the simulated observations: source fluxes are initially underestimated and approach true fluxes asymptotically at higher iterations. Finally, SPITS also proved the capability of such an imaging system (with the spiskymax algorithm) to reconstruct both extent and flux from an extended 511 keV source reasonably well. Many of the lessons learned with SPITS, namely concerning properties of the imaging algorithms, the simulation results, and the (unintended) recovery of the IRF spatial grid in the distribution of point source locations, can be transferred directly to SPI. For others, the properties of the SPITS dataset and the IRFs used have to be kept in mind: strong sources were imaged in a low-background laboratory environment, the sources were placed 9 m from the Ge detection plane, and the IRFs used are cruder than those available for SPI.Das "INTERnational Gamma-Ray Astrophysics Laboratory" (INTEGRAL) der Europäischen Raumfahrtbehörde ESA wurde am 17. Oktober 2002 gestartet. Es hat zwei Gamma-Teleskope, den Imager IBIS und das Spektrometer SPI, sowie Röntgen- und optische Monitore an Bord. Das Spektrometer SPI kann 20 keV - 8 MeV Photonen mit einer Auflösung von 2,3 keV bei 1,3 MeV messen; es verwendet hierzu 19 hochreine Ge-Detektoren. Eine kodierte Maske aus einer Wolframlegierung liefert räumliche Information mit einer Auflösung von ~2,5° in einem voll kodierten Blickfeld von 16°. Um die Abbildungseigenschaften von SPI detaillierter zu untersuchen, als dies während der Kalibration des Fluginstruments möglich war - die in den engen Zeitplan der Satellitenintegration eingefügt war -, erstellte ich das "SPI Imaging Test Setup" (SPITS) am Max-Planck-Institut für extraterrestrische Physik. SPITS besteht aus einer kodierten Maske und zwei Ge-Detektoren. Die kodierte Maske basiert auf einem SPI-Entwicklungsmodell und ist aus denselben Materialien wie die SPI-Maske. Die zwei hexagonalen Ge-Detektoren in ihren Al-Kappen stammen aus der Fluginstrumentfertigung und befinden sich in einer gemeinsamen Vakuumkappe. Sie können auf einem XY-Tisch bewegt werden, um die 19 Positionen der SPI Ge-Detektoren abzudecken. Daten von 11 Positionen des XY-Tisches werden zu einer SPITS-Messung von 19 Ge-Spektren kombiniert. Dies ist in einer Laborumgebung unter Verwendung von radioaktiven Quellen machbar, da weder Quellaktivität noch Hintergrund während einer Messung signifikant schwanken. Mit SPITS wurden drei verschiedene Quelltypen gemessen: punktförmige Laboreichquellen mit starken Linien zwischen 60 keV und 1836 keV, eine ausgedehnte 511 keV-Quelle, bestehend aus einer 88Y-Quelle und einer Bleischeibe, und mit Protonen bestrahlte Beschleunigertargets, die Photonen bis 9 MeV emittierten. Alle Quellen wurden 9 m von der SPITS-Detektorebene plaziert. Die Messungen mit punktförmigen Laborquellen deckten viele Einfallsrichtungen ab, die in den SPI-Eichmessungen nicht vorkamen - insbesondere sieben Einfallsrichtungen, die zum kleineren der standardisierten SPI-Pointierungsrastermuster zusammengesetzt werden können, sowie eine Reihe von Messungen, die das Synthetisieren von gerasterten Beobachtungen von zwei Quellen ermöglichen, die 0,5°, 1,0°, 1,5°, usw. voneinander entfernt sind. Weder ein hexagonales Rastermuster noch eine gerasterte Beobachtung von Quellen mit Entfernungen von weniger als 1° können aus den SPI-Kalibrationsdaten generiert werden. Außerdem wurde weder eine Abbildung von ausgedehnter Emission noch eine abbildende Messung von Quellen oberhalb 3 MeV während der SPI-Instrument-Kalibration versucht. Um das Bild des "Himmels" aus einer Dekonvolution der gemessenen Photonenanzahl in einer Linie in den 19 Ge-Detektoren zu erhalten, muß die Instrumentantwort auf Photonen aus allen möglichen Einfallsrichtungen bekannt sein. Die erforderlichen "Instrument Response Functions" (IRFs) für SPITS mit Quellen in 9 m Abstand wurden mit der Simulationsplattform für Teleskope mit kodierten Masken CAPTIF im "ray-tracing"-Verfahren erstellt. Ich diskutiere das CAPTIF-Massenmodell und vergleiche es mit einem GEANT-Massenmodell und gemessenen Eigenschaften von SPI- und SPITS-Komponenten. Nach Einführung eines Korrekturfaktors stimmen von den IRFs vorhergesagte und gemessene Detektorzählraten für zwei Einfallsrichtungen und mehrere Photonenenergien generell innerhalb 2 sigma überein. Beide SPI-Standardbildanalyseverfahren, spiskymax und spiros, wurden zur Analyse von SPITS-Daten herangezogen. spiskymax, primär für die Abbildung ausgedehnter Emission entwickelt, verwendet Entropiemaximierung, um die Flußverteilung zu bestimmen. spiros ("SPI Iterative Removal of Sources") ist in erster Linie für Punktquellen gedacht. In einem Cross-Korrelationsbild des Himmels wird die hellste (verbleibende) Quelle lokalisiert und anschließend im Datenraum subtrahiert; dieser Prozeß wird wiederholt, bis alle signifikanten Quellen gefunden sind. Da es kein klares, einfaches Kriterium für die Beendigung der Entropiemaximierungsanalyse gibt, habe ich das Verhalten von spiskymax mit simulierten Datensätzen studiert, um die optimale Iterationsanzahl für die SPITS-Punktquellenanalyse als Funktion der Quellstärke zu bestimmen. Die Fähigkeit von SPITS, eine Punktquelle zu lokalisieren, ist, wie erwartet, stark von der Signifikanz der Quelle und der Beobachtungsstrategie (mit oder ohne Rastern) abhängig; außerdem besteht eine leichte Abängigkeit vom Winkelabstand der Quelle zur Instrumentachse. Bei der Beobachtung von Labor-Punktquellen erreichen spiskymax und spiros auch ohne Rastern regelmäßig Lokalisierungsgenauigkeiten unterhalb 10'. Sowohl mit spiskymax als auch mit spiros finde ich eine Korrelation der rekonstruierten Quellpositionen mit den räumlichen Gitterpunkten am Himmel, für die die IRFs berechnet wurden. Beobachtungen von zwei Quellen konnten durch Addieren von Spektren, die mit einer Quelle an verschiedenen Positionen aufgenommen wurden, erzeugt werden. Auf dieser Basis kann die Fähigkeit des Abbildungssystems (Instrument, IRFs und Analysesoftware) bestimmt werden, zwei benachbarte Quellen zu trennen und korrekt zu lokalisieren. Selbstverständlich ist diese Fähigkeit wieder von der Signifikanz der Quellen abhängig. Bei nicht gerasterten Beobachtungen erweist sich spiros als nicht sehr verläßlich (grob korrekte Positionierung in weniger als 80% der Fälle), und die zwei hellsten Maxima im spiskymax-Bild sind selbst für Quellabstände über 2° oft mehr als 0,2° von den wahren Positionen entfernt. Rastern verbessert die Ergebnisse enorm: in allen spiros- und fast allen spiskymax-Rekonstruktionen von Quellen, die mehr als 1° voneinander entfernt sind, sind beide Quellen innerhalb von 0,2° korrekt lokalisiert. Zum Beispiel werden zwei 1° voneinander entfernte 22Na-Quellen von spiros in einer gerasterten Beobachtung auf 8' genau lokalisiert (auf 5' genau für größere Quellabstände). Auch die spiskymax-Rekonstruktionen der Beschleunigertargets in den jeweiligen Gammalinien ergaben für nicht gerasterte Beobachtungen von ein und zwei Quellen vernünftige Resultate - das 19F-Target zum Beispiel wird in mehreren Linien und an mehreren Positionen auf besser als 0,1° lokalisiert. spiros kann die Targets jedoch aus denselben Datensätzen oft nicht sinnvoll rekonstruieren. Das liegt wahrscheinlich an der Variabilität der "Quellaktivität", die die spätere Kombination von Messungen an den 11 XY-Tischpositionen zu einer Beobachtung problematisch macht. Diese Probleme treten nur mit spiros auf - vielleicht ein Anzeichen, daß dieser Algorithmus sensibler auf Diskrepanzen zwischen IRFs und wahrer Instrumentantwort reagiert. Die Flüsse der Laborquellen werden innerhalb der kombinierten statistischen und systematischen Fehler von spiskymax und spiros korrekt rekonstruiert. Der größte Beitrag zum Gesamtfehler ist die Unsicherheit in den IRFs und dem IRF-Korrekturfaktor, gefolgt von der Unsicherheit der Quellaktivität. Flüsse werden öfter unter- als überschätzt. Das passt sowohl zu der Tendenz der in den IRF vorhergesagten Zählraten, zu hohe Werte zu liefern, als auch zu einer Eigenschaft von spiskymax, die in den simulierten Beobachtungen sichtbar wurde: Quellflüsse werden initial unterschätzt und nähern sich bei höheren Iterationen asymptotisch den wahren Werten. Schließlich hat SPITS auch die Fähigkeit eines solchen Abbildungssystems (mit spiskymax) unter Beweis gestellt, Ausdehnung und Fluß einer flächigen 511 keV-Quelle recht gut zu rekonstruieren. Viele Ergebnisse der SPITS-Studie, so z.B. Eigenschaften der Abbildungsalgorithmen, Simulationsergebnisse und das (unbeabsichtigte) Wiederfinden der IRF-Gitter in der Verteilung der Punktquellenpositionen, können direkt auf SPI übertragen werden. Bei anderen muß man die Eigenschaften des SPITS-Datensatzes und der IRFs im Auge behalten: starke Quellen wurden in einer Umgebung mit niedrigem Hintergrund aufgenommen, die Quellen waren nur 9 m von der Detektorebene entfernt und die IRFs sind grober als die für SPI verfügbaren
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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