1,720,976 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
Changes in δ¹⁵N in pastoral soils under varying management intensity
No full textIn New Zealand, nitrogen (N) inputs and losses have increased dramatically following establishment (and subsequent intensification) of European style pastoral agriculture from the 1800s. An indicator that could identify soils which are most vulnerable to N loss would be useful to help target management practices aimed at reducing unwanted N losses. The natural abundance of ¹⁵N relative to ¹⁴N (δ¹⁵N) in soils is one potential indicator of N loss, because during most N transformations in soils, ¹⁴N is preferentially processed and lost (e.g. via ammonia volatilisation, denitrification or nitrate leaching). Therefore the overarching hypothesis for this thesis was that pastoral soils under intensive management regimes (with high N inputs, cycling and losses) would become progressively enriched with ¹⁵N relative to soils under less intensive management. This hypothesis was tested by measur ing δ¹⁵N in soils from four forest-to-pasture chronosequences, and in archived soils from six long-term (4–57 year) grazed field trials with different fertiliser or irrigation regimes.
Three of the forest-to-pasture chronosequences were on pumice soils where pine forests had been converted to dairy pastures. The fourth chronosequence was on a podzol soil in Northland, where native scrub had been converted to sheep grazed pastures. Surface soil δ¹⁵N on the pumice soil increased significantly from pine forests (2 ‰) to long-term pastures (4.1 ‰). In contrast, there was no clear relationship between pasture age and soil δ¹⁵N for the chronosequence on the podzol soil. The Northland soil displayed extreme podzolization and weathering, and had been previously disturbed by gum diggers, implying results could be relatively unique to this soil.
The two longest field trials were at Winchmore on the Canterbury plains, where different rates of superphosphate and irrigation had been applied for ~50 years. Soil δ¹⁵N increased more in treatments receiving higher rates of superphosphate or more frequent irrigation, and there were significant positive correlations between the average rate of change in soil δ¹⁵N, and total pasture production, clover production (thus N fixation) and calculated N losses.
Soil δ¹⁵N was also measured in archived soils from three long-term (¹⁵–25 year) superphosphate trials on North Island hill country. In these trials there were no consistent differences in soil δ¹⁵N between treatments. The shorter duration of the hill country trials (compared to the Winchmore trials), combined with smaller differences in pasture production between treatments and higher variability due to complex topography, may have contributed to the lack of observed differences between treatments. Indeed, slope and aspect did have a significant influence on soil δ¹⁵N with higher values on sheltered east facing slopes, and on easy slopes than steep slopes.
The final trial studied was a N fertiliser trial, in which N rates ranging from 0 to 750 kg ha–¹ y–¹ were applied to hill country pastures over a 4 year period. Soil δ¹⁵N increased significantly with time in treatments receiving >100 kg N ha–¹ y–¹, and the increase was more rapid as N rate increased. There was also a positive correlation between the rate of change in soil δ¹⁵N and nitrate leaching (p<0.001).
In general, results from this thesis showed that soil δ¹⁵N under intensively managed pastures (i.e. those receiving higher rates of fertiliser or irrigation) was higher than under less intensively managed pastures. It was concluded that higher soil δ¹⁵N in the more intensively managed pastures was most likely due to the influence that fertiliser or irrigation had on pasture production, N fixation by clover, and the flow on effects this had on animal stocking rates and N cycling and isotope fractionating loss processes. However, results from the hill country superphosphate trials and the chronosequence on the podzol soil, demonstrated that other factors (such as slope and aspect) can overwhelm or suppress the expected increases in δ¹⁵N in some situations. Therefore soil δ¹⁵N will probably be most accurate as an indicator of long-term management intensity, and management induced N losses, at sites with the same (or similar) topography, soils and climate.
Average rates of change in soil δ¹⁵N over the duration of the trials investigated in this thesis, ranged from –0.007 ‰ y–¹ to 0.35 ‰ y–¹, with rates of change being <0.1 ‰ y–¹ in all trials except the N rate trial (where N inputs were very high). This suggests that under ‘typical’ pastoral management regimes, any changes in bulk soil δ¹⁵N will probably only be detectable at decadal time scales.
A preliminary indicator of past management intensity and N inputs and losses was proposed for New Zealand soils, based on surface soil δ¹⁵N values. (1) Soils with δ¹⁵N values 5 ‰ will be from sites which have been intensively managed for a number of decades and subject to high N inputs and losses (e.g. N inputs >100 kg ha–¹ y–¹). More research will be required to further test the usefulness of this indicator. Key areas for future research include: gaining a better understanding of the effect of topography and soil type on soil δ¹⁵N, and making more direct measurements of the isotopic composition of different N inputs and outputs to more clearly identify mechanisms driving changes in soil δ¹⁵N in pastoral systems
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
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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