1,720,960 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
Modeling estuarine morphodynamics under combined river and tidal forcing
No full textEstuarine morphodynamics are of broad importance to estuaries’ functions related to navigation, human settlement and ecosystems. Inspired by the Yangtze River estuary (YRE), this study aims to explore the impact of river discharge, tides and their interaction on long-term estuarine morphodynamics. Use is made of 1D and 2D process-based models. In first instance we focus on purely hydrodynamic characteristics in a 560 km long basin. We analyze the non-stationary river tides in the YRE by harmonic analysis and continuous wavelet transformation which reveals a wide range of subtidal variations and non-linear modulation by varying river discharges. An intermediate river discharge could be defined at which the amplitudes of the internally generated overtides and compound tides reach maxima. Based on these hydrodynamic insights we conduct long-term (millennia time scale) morphodynamic simulations in schematized long basins. Vanishing spatial gradients in tidal residual sediment transport indicate an approach towards morphodynamic equilibrium. Morphodynamic equilibrium is also reached in case of a seasonally varying river discharge, which is reflected by a balance between erosion and accretion during low and high river discharge periods, respectively. River flow supplies sediment, accelerates ebb currents, and alters tidal asymmetries. Each of these processes has its own effects on tidal residual transport and morphodynamics. For example, the interaction between a mean flow (i.e., Stokes return flow or river flow) and tidal currents induces significant tidal residual sediment transport which explains net ebb transport dominance in the presence of a flood tidal asymmetry. A larger river discharge does not necessarily lead to deeper equilibrium bed profiles. An intermediate river discharge is found which induces largest residual sediment transport gradients along the estuary leading to deepest equilibrium bed profile. Quantification of this medium river discharge is case dependent because of the non-linearities involved. The 2D model approach applied in a large scale fluvio-deltaic system reveal river, estuarine and deltaic types of morphodynamic features, such as alternating sand bars, meandering channels inside the estuary and more elongated sand bars and distributary channels in the mouth zone and delta. The cross-sectionally averaged depth of the 2D model responds in a similar way to increased river discharge as a 1D model. Furthermore, a high river discharge induces ebb transport dominance, restricts development of flood channels and prolongs meander wavelength. In summary, this research unveils the fundamental effects of tidal asymmetries, river discharge, and river-tide interaction in governing residual sediment transport and associated long-term estuarine morphodynamics under combined river and tidal forcing.Hydraulic EngineeringCivil Engineering and Geoscience
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
Modelling the impact of sediment composition on long-term estuarine morphodynamics
No full textSediment composition, characterized by different contents of cohesive and non-cohesive sediments, is known to play a role on long-term estuarine and deltaic morphodynamics, but the exact impact is poorly understood. We establish a two-dimensional morphodynamic model to investigate the influence of different sediment compositions on the development of a schematic fluvio-deltaic system driven by river and tides. Though excluding the density effects, results suggest that the model captures the development of distributary channels and elongated sand bars with resemblance to that in the Yangtze Estuary. Sensitivity simulations show fundamentally different channel-shoal patterns take shape under different sediment compositions. Ebb dominance and associated seaward sediment flushing lead to faster morphodynamic development and more prograded delta under larger river discharge and sediment supply. We detect a positive correlation between the content of cohesive sediment and the speed of development, particularly cohesive sediment content is <50%. However, when the proportion of mud is larger (i.e., 50–75%), a deceleration of the morphological development occurs after 200 years. A sand-dominated environment exhibits the largest channel numbers and fast channel formation near the mouth within the first 300 morphodynamic years. Spatial distribution of bottom sediments changes with morphology, exhibiting increasing mud deposits near the mouth, whilst the sand remains inside the estuary. This study indicates the importance and need for a more realistic representation of bed compositions in long-term estuarine morphodynamic simulations.</p
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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