1,720,972 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
Probing the photochemical processes of Titan\u27s atmosphere
No full textIsomer-specific, spectroscopic studies of several CnH m species with n = 9 & 10, m = 8-12 have been carried out. Focus has been placed on species relevant to the formation or subsequent reactions of naphthalene and other fused ring systems in gasphase environments such as Titan’s atmosphere and in interstellar dust clouds. Massresolved, resonant two-photon ionization (R2PI) was used to record the jet-cooled, vibronic spectra of specific CnH m species. Double-resonant holeburning techniques were used as a means to collect structural isomer and conformer specific spectra. The ultraviolet spectrum of a new C10H8 isomer, 1-phenyl-1-butyn-3-ene, has been recorded and compared with other C10H8 isomers. Working off the hypothesis that alkylated benzenes may undergo ring closure to give fused ring species, conformationspecific spectroscopy of two radical recombination products, 4-phenyl-1-butene (C10H12) and benzylallene (C10H10), have been recorded, the former being the product of benzyl and allyl radicals, the latter of benzyl and propargyl radicals. It was found that upon photo-excitation, benzylallene undergoes hydrogen loss and ring closure to form naphthalene. It has been postulated that resonance-stabilized radicals (RSRs) play an important role in the formation of fused ring systems, including the aforementioned benzylallene to naphthalene mechanism. To that end, the visible spectroscopy and ionization thresholds of 1-phenylallyl (C9H9) and benzylallenyl (C10 H9) were recorded. The isomer-specific spectra and properties of three hydronaphthyl radicals, 1- and 2- hydronaphthyl (C10H 9), and 1,2,3-trihydronaphthyl (C10H11) have also been recorded. Hydrogenated naphthalenes may play a role in forming larger fused ring systems leading to tholins. They have also been postulated to play a role in the recycling of hydrogen in the interstellar media. Finally, the spectroscopy of two bicyclic compounds, diphenydiacetylene and diphenylvinylacetylene were explored as simple PAHs where the aromatic rings are not fused together, but are still conjugated
Laboratory Simulations Of Titan's Surface Composition And Its Relation To Atmospheric Haze Layers
Get PDFThe arrival of the Cassini spacecraft in orbit around Saturn has led to the discovery of benzene at ppm levels, as well as large positive ions evocative of polycyclic aromatic hydrocarbons (PAHs) in Titan’s atmosphere. Recently, the assignment of the band at 3.28 m as observed by the Visual–Infrared Mapping Spectrometer (VIMS) to gas-phase PAHs provides further evidence that these molecules are prevalent on Titan. These observations suggest that aromatic reaction pathways play an important role in the photochemistry of Titan’s atmosphere, in particular in the formation of large organic species. These aerosols eventually settle out of the atmosphere onto the surface of Titan giving rise to the different surface albedos that are observed by the VIMS instrument onboard Cassini.
We will present results from a laboratory study of the UV irradiation of ppm-level aromatic precursors to understand their influence on the observable characteristics of Titan’s surface. Spectroscopic measurements of our analog aerosols compare favorably to observations of Titan’s haze by VIMS and by the Composite Infrared Spectrometer (CIRS) in the far-infrared. In addition, the broad aerosol emission feature centered at approximately 145 \wn is of particular interest. From the broadness of this feature, we speculate that the emission is a blended composite of low-energy vibrations of large molecules such as polycyclic aromatic hydrocarbons (PAHs) and their nitrogen containing counterparts, polycyclic aromatic nitrogen heterocycles (PANHs). A further comparison of our aerosol spectra to the surface observations carried out by Cassini also shows a strong correlation between the aerosol makeup and the surface albedo of Titan. Using laser desorption mass spectrometry (LDMS) and collision-induced dissociation (CID) MS/MS techniques we confirm the presence of large (5+ rings) PAHs/PANHs in our aerosols and discuss possible formation pathways.Made available in DSpace on 2014-09-17T16:55:08Z (GMT). No. of bitstreams: 3
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Previous issue date: 2014-06-2
Oodles of undergrads underground: classroom undergraduate research at wind cave national park
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Previous issue date: 23For the past two years, the Department of Chemistry and Biochemistry at the University of Northern Iowa has been leading undergraduate students on spectroscopic expeditions into the depths of Wind Cave National Park in South Dakota. Using some of the newest miniaturized spectrometers, portable XRFs, and Lego Mindstorms Kits, the team has been working with NPS park rangers to look at the cave in a new light while providing unique experiences for the students involved
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
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