1,720,953 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Development of a sequential radiochemical procedure for irradiated graphite characterization in view of graphite-moderated nuclear reactor decommissioning
No full textLAUREA MAGISTRALEAi fini dello smantellamento di un’installazione nucleare, è necessario determinare accuratamente l’inventario radiologico ad essa associato. L’inventario radiologico consiste nella localizzazione, identificazione, caratterizzazione e quantificazione del materiale radioattivo presente all’interno della struttura. A partire dalla sua determinazione si ricava il vettore dei nuclidi, che permette di individuare la tipologia di radionuclidi emettitori presenti nella struttura e la corrispondente concentrazione di attività. La compilazione di un inventario radiologico puntuale permette di classificare i rifiuti nucleari sulla base del livello di radioattività e conseguentemente di selezionare le tecnologie e i metodi di trattamento specifici per la loro gestione. Inoltre, la sua determinazione consente di supportare le attività di smantellamento, garantendo condizioni di sicurezza per i lavoratori, il pubblico e l’ambiente, minimizzando i costi e rispettando i tempi. Escluso il nocciolo del reattore, la principale sorgente di radioattività è rappresentata dall’attivazione dei componenti in acciaio e dei materiali situati in prossimità del nocciolo. Per i reattori moderati a grafite, un rifiuto radioattivo problematico è costituito proprio dalla grafite irraggiata, per via del significativo volume coinvolto e per la presenza di radionuclidi a vita lunga. Infatti, l’inventario radiologico della grafite deriva principalmente dall’attivazione neutronica di impurezze presenti in concentrazioni in traccia, che in parte danno luogo a elementi radioattivi a vita lunga come 14C, 36Cl, 41Ca and 59Ni. Tra i prodotti di attivazione, alcuni di questi sono emettitori gamma mentre la maggior parte sono emettitori beta puri i quali richiedono l’applicazione di una procedura radiochimica prima di essere determinati. La concentrazione dei prodotti di attivazione può dipendere da diversi parametri, tra i quali si annoverano la composizione iniziale del materiale, le condizioni di burnup, la storia operativa del reattore ed il tempo trascorso dal suo spegnimento. Nel reattore nucleare di ricerca L-54M del CeSNEF situato presso il Politecnico di Milano, grafite ad elevata purezza è stata utilizzata come moderatore e riflettore. Il reattore è stato definitivamente spento nel 1979, dopo 20 anni di operazione, e da quel momento sono state condotte diverse attività preliminari di caratterizzazione. A questo proposito, è stato sviluppato dal laboratorio di radiochimica un modello di attivazione neutronica della grafite del reattore. Successivamente, è stata effettuata una caratterizzazione radiologica preliminare focalizzata sulla determinazione dei più significativi emettitori gamma, che ha permesso una prima validazione del modello.
In questo lavoro di tesi, è stata sviluppata una procedura radiochimica per la caratterizzazione della grafite irraggiata, al fine di validare ulteriormente il modello di attivazione neutronica della grafite del reattore L-54M. La procedura mira alla simultanea determinazione dei seguenti radionuclidi difficili da misurare, principalmente risultanti dall’attivazione delle impurezze della grafite: 3H, 14C, 36Cl, 129I, 55Fe, 59Ni, 63Ni, 41Ca and 90Sr. L’obiettivo di questo lavoro è proporre e ottimizzare, per mezzo di una campagna sperimentale, una procedura radiochimica sequenziale, affidabile e ripetibile da un punto di vista temporale, che possa essere applicata alla caratterizzazione della grafite irraggiata a supporto delle future attività di decommissioning. La procedura radiochimica sviluppata è finalizzata a separare sequenzialmente ciascun radionuclide dalla matrice e dagli elementi interferenti per la successiva misura di attività. Nell’ambito di questo lavoro, la procedura è stata messa a punto sulla base di un’approfondita ricerca di letteratura ed è stata testata su un campione di grafite non irraggiata al quale sono stati aggiunti degli opportuni carrier. La procedura si compone di un processo di digestione acida per la dissoluzione della matrice di grafite. Successivamente, ciascun analita è separato per mezzo di metodi radiochimici dedicati: co-precipitazione, distillazione, scambio ionico ed estrazione cromatografica. Infine, la resa chimica di ciascun analita a seguito di ogni step di separazione è determinata attraverso analisi all’ICP-MS. La procedura è stata attuata due volte, al fine di valutare la fattibilità di ciascuno step e proporre miglioramenti da adottare. Inoltre, la valutazione delle rese chimiche ha permesso di testare l’efficacia e la selettività di ciascun processo radiochimico.
La procedura radiochimica sviluppata in questo lavoro permetterebbe la completa caratterizzazione di un campione di grafite irraggiata in circa una settimana. Inoltre, potrebbe essere adattata alla caratterizzazione di differenti matrici, come acciaio e cemento attivati.In decommissioning of a nuclear facility, the resulting radiological inventory needs to be accurately assessed. It involves the localization, identification, characterization and quantification of radioactive materials within the nuclear installation. Moreover, it enables to define the nuclide vector, which consists in the list of radionuclides present in the facility and their activity concentration. A detailed and accurate description of the nuclide vector is fundamental to classify nuclear waste according to its radioactivity content and to select the suitable technologies and techniques required for its management. Moreover, the assessment of the nuclide vector allows to support dismantling activities, ensuring their management in safety conditions for personnel, public and environment, minimizing costs and saving time. Apart from reactor core, the main radioactivity arises from neutron activation of steel components and materials close to the core. Anyway, for graphite-moderated reactors, irradiated graphite constitutes a problematic radioactive waste, due to the large volumes involved and to the presence of long-lived radionuclides. In fact, the radiological inventory mainly derives from activation of trace impurities exposed to neutron irradiation, which partially result in long-lived elements such as 14C, 36Cl, 41Ca and 59Ni. Among activation products, few of them are gamma emitters while the others are pure beta-emitting radionuclides which require a radiochemical procedure before their determination. The concentration of activation products may depend on several parameters, such as: the initial nuclide composition, burnup conditions, reactor power history, time elapsed from shutdown. In CeSNEF L-54M nuclear research reactor of Politecnico di Milano, high purity nuclear grade graphite had been used as moderator and reflector material. The reactor was definitively shut down in 1979, after 20 years operation, and since that some characterization activities have been carried out. In this regard, a neutron activation model of graphite stack was developed by the radiochemistry laboratory. Subsequently, a preliminary radiological characterization focused on the most significant gamma-emitting radionuclides was performed, which allowed to validate the model.
In this thesis’ work, a radiochemical procedure for characterization of irradiated graphite has been developed in order to further validate the neutron activation model of L-54M graphite stack. The procedure aims at simultaneously determining the following hard to measure radionuclides, mainly resulting from activation of graphite impurities: 3H, 14C, 36Cl, 129I, 55Fe, 59Ni, 63Ni, 41Ca and 90Sr. The scope of this work is to propose and optimize, by means of an experimental campaign, a sequential, reliable and time-effective radiochemical procedure for the radiological characterization of irradiated graphite to aid forthcoming decommissioning activities. The radiochemical procedure is intended to sequentially separate each nuclide from the matrix and from interfering elements for the subsequent activity measure. In this work, the procedure has been developed on the basis of a deep literature research and tested on a non-irradiated graphite sample with the addition of proper carrier’ solutions. The procedure involves an acid digestion treatment for the dissolution of the graphite matrix. Subsequently, each analyte is separated by means of dedicated radiochemical methods: co-precipitation, distillation, ion exchange and extraction chromatography. Finally, the chemical yield of each analyte after the separation steps is assessed by ICP-MS analysis. The procedure has been tested twice, in order to evaluate the feasibility of each step and propose further improvements. Moreover, evaluation of chemical yields has enabled to test the effectiveness and selectivity of each radiochemical process.
The radiochemical procedure developed in this work could enable the complete radiological characterization of a graphite sample in about one week. Moreover, it could be adapted and applied to different matrices, such as concrete and steel
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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