1,720,988 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
Seasonal micronutrients concentration in leaves of four forest species from Parque Chaqueño, Argentina
No full textFil: Prause, Juan. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.Fil: Fernández López, Carolina. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.El ciclo de nutrientes es uno de los componentes fundamentales en el funcionamiento de los ecosistemas forestales. Las hojas de diferentes especies forestales muestran distinta composición química y diferencias estacionales en la producción de biomasa atribuidas a las fluctuaciones climáticas y/o cambios en la fenología de las plantas y a la variación en el contenido de nutrientes. El objetivo del trabajo fue analizar la variación estacional de las concentraciones de Fe, Mn, Cu y Zn en hojas de: Gleditsia amorphoides (Ga), Patagonula americana (Pa), Maclura tinctoria (Mt) and Astronium balansae (Ab). El sitio de estudio fue localizado en la Reserva Natural Estricta de Colonia Benítez (Chaco, Argentina). Las hojas de cada especie forestal fueron recogidas mensualmente, secadas a 70oC, se determinó su peso seco y posteriormente se molió. El análisis foliar se realizó por oxidación húmeda empleando una mezcla ternaria HNO3-H2SO4-HClO4. Después de la digestión la concentración total de micronutrientes foliares fue determinada por espectrometría de absorción atómica. Las mayores concentraciones de Fe fueron para Mt (76.1mg/kg), Pa (75.2mg/kg), Ab (59.5mg/kg) y Ga (45.3mg/kg). En Mn las más altas concentraciones se detectaron en Pa (54.0mg/kg), Ga (50.0mg/kg), Mt (48.0mg/kg), y la menor en Ab (39.7mg/kg). No se hallaron diferencias significativas entre las especies forestales para Cu foliar en Pa (11.3mg/kg), Ga y Mt (11.0mg/kg) y Ab (10.4mg/kg). Las mayores concentraciones foliares de Zn fueron en Mt (347.4mg/kg), Ga (319.9mg/kg), Pa (280.2mg/kg) y Ab (255.7mg/kg). En las especies forestales estudiadas, la concentración de los micronutrientes analizados mostró una errática variación estacional, que puede ser atribuida a las relaciones establecidas entre las especies nativas bajo la fuerte influencia del ambiente, especialmente temperaturas y precipitaciones, durante un largo período de tiempo.Nutrients cycling is a fundamental component in the functioning of forest ecosystems. Leaves of different forest species observe specific chemical composition, and some seasonal differences in biomass production, may be related to climate fluctuations and/or changes in plant phenology and the variation on nutrient contents. The objective of this study was to analyze the seasonal variability of Fe, Mn, Cu and Zn concentrations in leaves of Gleditsia amorphoides (Ga); Patagonula americana (Pa); Maclura tinctoria (Mt) and Astronium balansae (Ab) from Colonia Benítez Strict Nature Reserve (Chaco, Argentina). The leaves of each forest species were collected monthly, dried at 70oC and their weight by tree species were recorded. Samples for analytical determinations were prepared by humid oxidation of organic substances from vegetal nets, using oxidant acids such as ternary mixture of HNO3-H2SO4-HClO4. After digestion, total micronutrients leaves concentrations were determined by atomic absortion spectrophotometry. Leaves Fe highest values were detected during fall in Mt (76.1mg/kg), Pa (75.2mg/kg), Ab (59.5mg/kg) and Ga (45.3mg/kg). Highest foliar concentrations of Mn were detected in Pa (54.0mg/kg), Ga (50.0mg/kg), Mt (48.0mg/kg), and Ab with the lower Mn concentration (39.7mg/kg). No significant differences were found for Cu between the different forest species, standing for Pa (11.3mg/kg), Ga and Mt (11.0mg/kg) and Ab (10.4mg/kg). With regard to leaves Zn, highest concentrations were found in Mt (347.4mg/kg), Ga (319.9mg/kg), Pa (280.2mg/kg) and Ab (255.7mg/kg). Generally, a marked seasonal
variation was observed for Mn and Cu concentrations (except in Ga) and Zn (except in Pa), with no statistical
differences for Fe. In the species studied, the concentration of micronutrients analyzed showed a marked and erratic seasonal variation, attributed to the relationship established between the native species, and the strong influence of the environment over a long period of time, especially temperature and rainfall
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
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
Cambios en contenido de fósforo, nitrógeno y materia orgánica luego de una reforestación con Pinus Elliottii, en el parque chaqueño
No full textGeneralmente los suelos forestales, o no han sido nunca cultivados o han sido
abandonados por la agricultura y presentan propiedades físicas y químicas poco
favorables para la implantación de árboles. Muchos han resultado empobrecidos
por el pastoreo o por la recolección de materia orgánica, o de vegetación
destinada al abonado de las tierras agrícolas (Bonneau, 1978). Los objetivos de
este trabajo fueron: a) evaluar los cambios edáficos producidos por la introducción
de Pinus elliottii en el Parque Chaqueño Húmedo; b) cuantificar los contenidos de
Fósforo, Nitrógeno y Materia Orgánica en un suelo reforestado con Pinus elliottii
respecto al suelo con vegetación nativa. Para ésto se localizó un ecosistema
forestal con una especie introducida con más de 30 años de implantadas de Pinus
elliottii donde se seleccionaron cinco (5) árboles en condiciones sanitarias
similares y tamaño. Además, se ubicaron dos parcelas con vegetación nativa,
próximas a cada una de las forestaciones, cuyos suelos sirvieron como testigos.
Se procedió a realizar la identificación de los diferentes suelos y posteriormente se
efectuaron los muestreos, éstos fueron realizados en el año 2013 a diferentes
profundidades; en la plantación y los sitios testigos fueron muestreados a un
mismo intervalo, de acuerdo a las características edáficas halladas en el área de
trabajo y según la descripción edafológica de los perfiles de suelos en la
forestación. Una vez obtenidas las muestras fueron llevadas al laboratorio donde
se secaron, molieron y tamizaron para realizar los diferentes análisis: pH, textura,
densidad aparente, materia orgánica, fósforo disponible. El diseño utilizado para
este trabajo fue en parcela dividida con cinco repeticiones. Con los datos
obtenidos para cada profundidad se realizó un análisis de medias entre suelo
testigo y tratamiento para cada variable y un análisis de componentes principales
para establecer la participación de éstas respecto a los sitios. Con el análisis de
los datos se pudo concluir que en los sitios con Pinus elliottii el aporte de materia
orgánica se incrementa con respecto al testigo. Las variables químicas no son tan
representativas en estos sitios entre tratamiento y testigo
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
