1,721,282 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
Cálculo por dinámica y mecánica molecular de sitios y calores de adsorción de dipentenos sobre zeolita y
No full textHemos utilizado métodos de la mecánica molecular para estudiar la adsorción de R-limoneno, p-ment-1-eno, p-ment-8-eno y p-mentano sobre faujasita silícea y sobre zeolitas Y con relación Si/Al = 2 que contenían diferentes cationes en el sitio SII (Nal+, Fe2+, FeH y MnH). Los cálculos mostraron que la presencia de dobles enlaces en la molécula que se adsorbe y el tipo de catión en SIl determinan la estabilidad del complejo adsorbatozeolita. Las interacciones entre el huésped y la molécula adsorbida estuvieron dominadas por las contribuciones electrostáticas, las cuales aumentaron con la carga del catión en SII. La orientación de las moléculas insaturadas en la supercaja fue resultado del balance entre el aumento de repulsiones estéricas entre zeolita y molécula adsorbida y el aumento de atracciones electrostáticas como resultado de la minimización de dos grupos de distancias: las distancias entre el catión en SII y los carbonos Sp2 de la molécula adsorbida y las distancias entre los oxígenos estructurales de la zeolita y los hidrógenos de la molécula adsorbida.We have used molecular mechanics methods to study the adsorption of R-limonene, p-menth-l-ene, p-menth-8-ene,and p-rnenthane on siliceous faujasite and zeolites Y with Si/Al = 2, which contained different cations at site SII (Nal+,Fe2+, Fe3+, and MnH). The calculations showed that the presence of double bonds on the adsorbate and the type of cation on SII determine the stability of the adsorbatezeolite complexo Host-guest interactions were dominated by electrostatic contributions, which increased with the charge on the cation at SII. The orientation of the unsaturated adsorbates in the supercage resulted from the balance between steric repulsions and the minimization of two sets of distances: those between the cation at SII and the Sp2 carbons on the guest, and those between frameworkoxygens and hydrogens on the guest
Plantas aromaticas y aceites esenciales: estudio y viabilidad de su desarrollo en colombia.
Get PDFThe talk presents details of the historical essential oil development as well as
some economic and chemical aspects, and a description of the structure of the
essential oils productive and value chains. Several aspects of the botanical,
molecular and bioactivity diversities found within essential oils are discussed.
Scientiometry is presented as a guiding beacon for the research strategies on
essential oils. As an example, the case of the essential oils and the bioactivity
found in the genus Lippia, is discussed. Several scenarios for the development
of the essential oils agroindustry are presented, together with their relationship
with different factors that determine their economic feasibility.En la conferencia se presentan detalles del desarrollo histórico, aspectos
químicos y económicos de los aceites esenciales, y se describe la estructura de
las cadenas productiva y de valor de los aceites esenciales. Se tratan aspectos de
las diversidades botánica, molecular, y de bioactividad que presentan los aceites
esenciales. Se discuten las estrategias de investigación sobre aceites esenciales,
a la luz de la cienciometría. Como ejemplo se presenta el caso de los aceites
esenciales y la bioactividad encontrada en el género Lippia. Se plantean varios
escenarios para el desarrollo de la agroindustria de aceites esenciales, junto con
su relación con diferentes factores que determinan su viabilidad económica
Establishment of a technique of analysis chromatographyc for determine n-methylcarbamates and their metabolites in water samples.
No full textEl monitoreo de los N-metilcarbamatos es importante, son insectidas utilizados en el control de plagas en los cultivos de café, maíz, hortalizas, cítricos y flores, entre otros; por su solubilidad, pueden contaminar los suelos y las fuentes de agua superficiales y subterráneas. Estos plaguicidas son tóxicos, afectan la salud de los seres humanos y muchas especies de peces y invertebrados. Para la determinación de estos plaguicidas en las aguas existen técnicas como Limperos y ranta, cromatografía líquida (LC) y Cromatografía de gases (GC). Sin embargo, la cromatografía de gases sobresale por su sensibilidad, resolución y costo moderado. En el presente trabajo se implementó una técnica para la determinación, por cromatografía de gases de los N-metilcarbamatos y sus productos de degradación, a través de la derivación con anhídrido trifluroacético. La técnica se caracterizó por su buena reproducibilidad y resolución y por sus bajos niveles mínimos de detección (0.5 – 3.3 mg/L). Adicionalmente, se estudió la recuperación de los N-metilcarbamatos de muestras de agua por las técnicas de extracción: líquido-líquido continuo (CLLE), líquido-líquido por lotes (BLLE) y extracción en fase sólida (SPE). Para CLLE se obtuvo los mejores porcentajes de recuperación para la mayoría de los N-metilcarbamatos estudiados. La técnica desarrollada se aplicó para evaluar la presencia de N-metilcarbamatos en muestras de agua superficial de las quebradas Menzuly y La Grande. Según los resultados, no hay presencia de los plaguicidas estudiados, por encima del nivel mínimo de detección del sistema empleado HRGC/m-ECD. Los resultados de este trabajo pretenden ser una base para futuras investigaciones y programas de control de los N-metilcarbamatos en muestras de aguas, frutos y suelos.PregradoQuímicoN-methylcarbamates, Derivatization, Gas chromatography, Extraction, Pesticides, water, determinatio
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