1,720,963 research outputs found
Monitoring grassland carbon sequestration in central Kazakhstan with remote sensing and carbon cycle modelling
No full textA remote sensing based monitoring system for discrimination between climate and human-induced vegetation change in Central Asia
No full textPurpose – This paper aims to demonstrate the importance of taking into account precipitation and
the vegetation response to it when trying to analyse changes of vegetation cover in drylands with high
inter-annual rainfall variability.
Design/methodology/approach – Linear regression models were used to determine trends in
NDVI and precipitation and their interrelations for each pixel. Trends in NDVI that were entirely
supported by precipitation trends were considered to impose climate-induced vegetation change.
Trends in NDVI that were not explained by trends in precipitation were considered to mark
human-induced vegetation change. Modelling results were validated by test of statistical significance
and by comparison with the data from higher resolution satellites and fieldtrips to key test sites.
Findings – More than 26 percent of all vegetated area in Central Asia experienced significant
changes during 1981-2000. Rainfall has been proved to enforce most of these changes (21 percent of the
entire vegetated area). The trends in vegetation activity driven by anthropogenic factor are much
scarcer and occupy about 5.75 percent of the studied area.
Practical implications – Planners, decision makers and other interest groups can use the findings
of the study for assessment and monitoring land performance/land degradation over dry regions.
Originality/value – The study demonstrates the importance of taking into account precipitation and
the vegetation response to it when trying to analyse changes of vegetation cover in drylands with high
inter-annual rainfall variability
Modelling Carbon Sequestration in Drylands of Kazakhstan Using Remote Sensing Data and Field Measurements
No full textLandsat ETM+ data were related with field measurements of carbon stocks residing in the vegetation and in the soil along a 230 km west-east transect within Kazakhstan’s grassland zone. The biomass carbon was correlated to the mid-infrared corrected Normalized Difference Vegetation Index (NDVIc). Soil carbon responded most strongly to the multi-spectral features of the Kauth-Thomas transformation (KT) and was modelled using the non-linear multiple regression. Retrieved models were applied to the Landsat ETM+ image and carbon stocks were mapped over Shetsky district of Karaganda province at the pixel-by-pixel scale. Total terrestrial carbon stocks estimated for the area of Shetsky district account to 97.2 million tons, whereas most part of it (97.6%) is residing in soil
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
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