1,720,964 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Laser-induced plasma underwater: spectroscopic applications, enhancement of the emission and bubble cavitation
No full textUn laser a 1064 nm, con doppio impulso di durata in nanosecondi, è stato utilizzato per generare sott’acqua il plasma ed il segnale LIBS (Laser Induced Breakdown Spectroscopy).
Con la tecnica LIBS sono stati analizzati sott’acqua diversi campioni solidi anche con superficie rugosa; i materiali esaminati corrispondono a quelli ritrovabili nei siti archeologici sottomarini, con lo scopo di riconoscere in-situ gli oggetti di valore per una successiva estrazione o restauro sul posto. I risultati qui ottenuti dimostrano la fattibilità nel riconoscere con LIBS le leghe preziose e quelle di rame, e di distinguerle da altri materiali comuni come ad esempio il ferro. Sui bronzi sommersi, sono state ottenute anche delle analisi quantitative che consentono la datazione dei reperti. Inoltre è possibile distinguere i marmi dalle rocce calcaree comuni.
Allo scopo di aumentare la sensibilità della tecnica LIBS applicata sott’acqua, è stata definita una procedura per l’acquisizione e l’elaborazione dei dati, chiamata “filtraggio degli spettri”. Questa procedura ha permesso di aumentare il rapporto segnale-rumore per un fattore 4 sui campioni solidi e sui sedimenti sommersi, e per un fattore 7 nel caso delle analisi delle impurità nell’acqua.
Le misure LIBS sono state effettuate anche sui sedimenti in acqua; in questo caso, le onde d’urto generate dal laser causano la formazione di una densa nube di particolato appartenente al sedimento. Queste particelle scatterano sia la radiazione laser sia quella del plasma e spesso inducono la formazione del plasma sopra la superficie esaminata. A causa delle forti oscillazioni nella posizione e nei parametri del plasma, è stato possibile ottenere delle analisi quantitative solo dopo un’appropriata selezione degli spettri con parametri del plasma simili. Questa selezione è stata basata sulla distribuzione spettrale dell’emissione continua del plasma. L’importanza di questi risultati riguarda la possibilità di misurare in-situ la composizione superficiale dei sedimenti, utile ad esempio per l’esplorazione dei laghi subglaciali e per il monitoraggio dell’inquinamento dei fondali di laghi, fiumi e mari.
Infine, le analisi LIBS sono state condotte sulle impurità dell’acqua, considerando tre elementi: Mg, Mn e Cr. Inizialmente, per il Mg è stato ottenuto il limite di rilevamento di 0.21 ppm; in seguito è stato notato che per le energie intermedie d’impulsi laser la soglia di rilevamento LIBS si riduce per un ordine di grandezza corrispondente a 33 ppb per il Mg, 390 ppb per il Mn e 920 ppb per il Cr. È anche stato studiato l’effetto matrice nelle analisi LIBS. Risulta che l’aggiunta di qualsiasi impurità all’acqua distillata causa un allungamento del plasma e di conseguenza una riduzione dell’energia accoppiata nel punto focale. Questo effetto è responsabile per la veloce saturazione delle curve di calibrazione e per l’aumento della soglia di rilevamento con la salinità dell’acqua.
Nella parte finale di questa tesi, sono state studiate le cause per l’aumento del segnale LIBS per le energie intermedie d’impulsi laser. La formazione del plasma e della bolla di vapore sono stati monitorati tramite Mie scattering, la tecnica fotografica e gli spettri LIBS. Contemporaneamente, sono stati monitorati l’energia e la forma d’impulsi laser; è stato notato che la riduzione del ritardo tra il primo trigger del Q-switch, applicato per ridurre l’energia laser, risulta nella formazione d’impulsi multipli. I risultati più importanti qui ottenuti sono i seguenti: un’efficiente e localizzata formazione del plasma e della bolla di vapore ha un limite superiore di energia laser; gli impulsi di energia più elevata causano un allungamento del plasma e la formazione di multiple sferiche bolle di vapore lungo il passaggio del fascio laser; queste bolle scatterano la radiazione d’impulsi laser successivi applicando una sequenza di impulsi a bassa energia prima dell’ultimo impulso, sia il plasma sia la bolla sono ben localizzati e la bolla è più espansa; la presenza di un piccolo impulso prima dell’ultimo (analitico per LIBS) è responsabile di un fortissimo incremento nell’accoppiamento laser-bolla e, quindi, per una estremamente intensa emissione del plasma secondario.
Nelle sperimentazioni qui descritte, è stata usata una singola sorgente laser applicando due trigger esterni per il Q-Switch. Gli impulsi multipli sono stati ottenuti riducendo il ritardo del primo trigger, in modo di operare vicino alla soglia laser, inducendo le oscillazioni di rilassamento.Double-pulse, nanosecond laser excitation at 1064 nm was applied to generate plasma underwater and to perform Laser Induced Breakdown Spectroscopy (LIBS).
By LIBS technique, different solid samples also having rough surfaces, were analyzed underwater. The materials considered are those that can be found in marine archaeological parks, in view of in-situ recognition of the materials/objects valuable for extraction or in-situ restoring. The obtained results demonstrate that both precious alloys and copper-based alloys can be clearly identified and distinguished from other common materials such as iron. On the submerged bronze samples, also quantitative analysis were obtained, allowing the approximate object dating. Furthermore, it was possible to distinguish by LIBS marble materials from common calcareous rocks.
In order to improve the LIBS signal underwater, a procedure for multi-shot signal acquisition and processing was developed, here called spectral filtering. This procedure allowed to increase Signal-to-Noise Ratio up to a factor 4 on the immersed solid or soft samples, and up to a factor seven in bulk liquid analyses.
LIBS was also applied for analyses of immersed sediments. In such case, the laser-induced shock waves creates a dense particle cloud above the analyzed soft material, which scatter the laser and plasma radiation, and sometimes induce the breakdown formation above the analyzed surface. Due to strong shot-to-shot variations of the plasma location and properties, quantitative analyses were obtained only after developing an additional data filtering procedure. The latter regards automatic selection and summing only the spectra with similar plasma properties, identified through spectral distribution of the plasma continuum. An importance of this work is related to a possibility to measure in-situ the composition of top sediment layers, interesting for sub-glacial lake exploration and pollution detection of sea or river bottoms.
The last step in underwater LIBS analyses regards liquid impurities, where three elements were considered: Mg, Mn and Cr. The initially obtained detection limit for Mg in pure water was 0.21 ppm. Successively, it was observed that for mid laser pulse energies a tenfold reduction of the LIBS detection limits occurs, corresponding to 33 ppb for Mg, 390 ppb for Mn and 920 ppb for Cr. The influence of the matrix effect, i.e. liquid impurities and water salinity on the LIBS signal was also studied. It was found that any solute addition to pure water progressively elongates the plasma and this effect causes the reduction of the laser radiation coupled to the focal point. As a consequence, calibration curves show fast saturation and the detection limits increase with water salinity.
In the final part of this dissertation, the reasons for the LIBS signal improvement at mid laser pulse energies were investigated. The underwater plasma and bubble formation was studied by Mie scattering on laser-induced bubbles, by a fast and conventional photography, as well as from the spectral (LIBS) analyses. Contemporary, the pulse energies and shape were always monitored and it was observed that at low first pulse energies, obtained by reducing delay of the first Q-switch trigger, a multi-pulse sequence was present. The most important here obtained results can be summarized in the following: efficient; localized plasma and gas bubble formation in water (and other liquids) has an upper laser energy limit; higher energy pulses lead to the plasma elongation and formation of multiple spherical bubbles along the beam path, which scatter the incoming radiation from the successive laser pulse; by using a sequence of low-energy multi-pulses before the last laser pulse, both the plasma and gas bubble remain well localized and the bubble highly expanded; presence of a small pulse before the last one (analytical pulse for LIBS) is responsible for a tenfold increase in its coupling to the bubble, thus to an extremely intense secondary plasma emission.
In all the experimentations here reported, a single laser source was used by applying two external Q-Switch triggers to produce two laser pulses during a single lamp flashing. Multi-pulse sequence was obtained by reducing the first Q-Switch trigger delay to operate close to the population inversion where the relaxation oscillations occur
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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