1,721,048 research outputs found
Estimation of moisture fluxes in East Antarctica and their impact on the isotopic composition of the snow surface
Full text linkThe ability to infer past temperatures from ice core records has in the past relied on the
assumption that after precipitation, the stable water isotopic composition of the snow surface
layer is not modified before being buried deeper into the snowpack and transformed into ice.
However, in extremely dry environments, such as the East Antarctic plateau, the precipitation is so
sparse that the surface is exposed to the atmosphere for significant time before burial. During
that exposure, several processes have been recently identified as impacting the snow isotopic
composition after snowfall: (1) exchanges with the atmosphere (i.e. sublimation/condensation
cycles), (2) wind effects (i.e. redistribution and pumping) and (3) exchanges with the firn below (i.e.
metamorphism and diffusion).
Here we present the data over several seasons and years of the atmospheric water vapor and
snow surface isotopic composition at Dome C, East Antarctica. To understand the link between
these two elements, we investigate the moisture fluxes at the surface of the ice sheet, at the snowair
interface. No eddy-covariance measurements are available for the recent years, we therefore
make use of the available primary meteorological parameters measured continuously on site to
estimate the surface moisture fluxes using the bulk method. We estimate that the cumulative
effect of the moisture fluxes is positive: about 12% of the mean annual accumulation is sublimated
away. Alongside, we see an enrichment in d18O in the snow surface during the summer months,
when most of the moisture fluxes are taking place. The snow d-excess is also affected and evolving
in anti-phase with d18O. This indicates occurrence of fractionation during sublimation in line with
previous field and laboratory studies. The moisture fluxes could be a key driver of changes in the
snow isotopic composition between precipitation events influencing the climate signal stored in
the isotopic record of ice cores
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
Recommended from our members
A global database of water vapor isotopes measured with high temporal resolution infrared laser spectroscopy
Full text linkThe isotopic composition of water vapour provides integrated perspectives on the hydrological histories of air masses and has been widely used for tracing physical processes in hydrological and climatic studies. Over the last two decades, the infrared laser spectroscopy technique has been used to measure the isotopic composition of water vapour near the Earth's surface. Here, we have assembled a global database of high temporal resolution stable water vapour isotope ratios (delta O-18 and delta D) observed using this measurement technique. As of March 2018, the database includes data collected at 35 sites in 15 Koppen climate zones from the years 2004 to 2017. The key variables in each dataset are hourly values of delta O-18 and delta D in atmospheric water vapour. To support interpretation of the isotopologue data, synchronized time series of standard meteorological variables from in situ observations and ERA5 reanalyses are also provided. This database is intended to serve as a centralized platform allowing researchers to share their vapour isotope datasets, thus facilitating investigations that transcend disciplinary and geographic boundaries
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
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
- …
