1,720,985 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
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
Evaluation of the wheel-point and step-point methods of veld condition assessment.
No full textA number of aspects of a technique recently developed to assess the agro-ecological condition of veld were evaluated by 4 independent observers. Measuring the veld composition score yielded relatively repeatable results with a 95% confidence limit of (6,43 units for any single estimate which may range from 0 to 100 units. The step-point method yielded results on percentage veld composition and on veld composition score which did not differ in precision or in absolute amount from those obtained using the wheel-point apparatus. Adoption of the step point method in preference to the wheel-point method saves in equipment and manpower, and renders the technique usable by extension officers estimate of basal cover, and perhaps should not be used on uneven terrain or bushy veld. Using a circular-quadrat 3,5 cm in diameter yielded a more precise index of basal cover than did the standard method using a point-quadrat 1 mm in diameter. However, there are disadvantages in using the relatively large quadrat. Possible bias introduced into determining percentage species composition and composition score by using the nearest plant method were negligible.Keywords: basal cover; measuring; precision; quadrat; range; species composition; step-point method; technique; veld condition assessment; wheel-point metho
Are multi-paddock grazing systems economically justifiable?
No full textThe financial implications of few- and multi-paddock systems were modelled by a discounted cash flow analysis with the (discounted) present value as the dependent variable, and number of paddocks, farm run-down time, time horizon and discount rate as the independent variables. Present values were higher for few- than for multi-paddocks where rundown was slow, time horizon short and discount rate high. Present values were always higher for few- than for multi-paddocks when time horizon was short. At high discounts, present values over all modelled time horizons were higher for few- than multi-paddocks. Even if the conservation ideal of zero or low discounts obtains, there is little financial incentive for multi-paddocks for farmers with short planning horizons. Remedy of this by state aid and tax concessions has been tried. Success is not obvious, perhaps because subsidy has reduced farming costs and thereby prompted faster or greater resource depletion.Language: EnglishKeywords: conservation; Continuous grazing; discount rate; Discount rates; farming; grazing; grazing systems; modelling; planning; present value; Present values; Range deterioration; Rotational grazing; south afric
The effect of animal size and adaptation on defoliation, selective defoliation, animal production and veld condition.
No full textA conceptual model of the veld-herbivore relationship is presented. Large-sized, largely grazing animals feed relatively unselectively on abundant roughage. The carrying capacity of veld for them is high. They are low producers per animal, but high producers per ha. Per unit of metabolic mass they have a relatively minor effect on veld condition. Browsers and small-sized, largely grazing animals select strongly for concentrated food. The carrying capacity of veld for them is low. They are excellent converters per animal and per unit mass of intake. Their production per ha is low. One-animal-species models have been quantified readily. The complexity of two- or more-species models at present makes them prohibitively expensive and laborious to quantify. Two simplifications, one of which is readily testable, are proposed to circumvent the impasse.Keywords: animal production; browsers; carrying capacity; defoliation; grazing; intake; metabolic mass; modelling; models; production; selective defoliation; south africa; veld conditio
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