1,720,984 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
Transparent Exopolymer Particles in the Surface Arctic Ocean by Ocean Biogeochemistry Modeling
No full textIn light of the Arctic Amplification of global warming, it is fundamental to enhance our comprehension of ecosystem dynamics in the Arctic Ocean. This will facilitate predictions about how alterations in phytoplankton and broader ecological processes may evolve under future warming scenarios. The primary production of the Arctic Ocean is principally based on phytoplankton building up organic carbon. The growth and distribution of phytoplankton are strongly shaped by the seasonality of polar night and day, sea ice cover and nutrient availability. Focusing on one essential component of the organic carbon cycle, I simulate transparent exopolymer particles (TEP) in the upper ocean. As in situ observations are scarce, modeling can extend our knowledge on their spatial and temporal occurrence patterns and trends. Additionally, these particles have recently been reported to act themselves as biogenic aerosol precursors, or as precursor for other organic compounds. These may be an important source of primary marine organic aerosols in the Arctic atmosphere.
In the first part of my dissertation, I present a coupled ocean sea-ice biogeochemistry model where I integrate dissolved acidic polysaccharides (PCHO) and TEP. Phytoplankton exude organic carbon into the surrounding ocean, particularly under nutrient-depleted conditions. PCHO are defined as one part of the exuded organic carbon, which can then aggregate to form larger particles, such as TEP. There is a strong seasonal cycle of TEP in the upper ocean, as the occurrence of TEP follows the phytoplankton blooms both temporally and spatially. The simulation provides an initial estimate of TEP concentration with the highest levels reaching 200-400 µg C/L in the upper ocean (0-30 m depth) simulated in the Fram Strait and on the continental shelves under conditions of nutrient depletion for June to August. In the central basins, TEP concentration range from 10 to 50 µg C/L. When considered in the context of observation datasets, this simulation performs well in terms of Total Chlorophyll a (TChla) and particulate organic carbon. There is reasonable agreement for TEP compared with the few in situ datasets available. It would be recommended to gather more observational data on TEP in conjunction with data on TChla and other relevant biogeochemical parameters. This would allow deeper insights into the ecosystem dynamics and time series of TEP in the Arctic Ocean. As a consequence of the simulation analysis, the regions of interest for in situ measurements should be the marginal ice zones, and especially the high Arctic due to the seasonal variations of sea ice and its overall declining trend.
Moreover, the simulation for the period 1990 to 2019 indicates a significant negative trend of TEP concentration in summer in regions affected by the inflow of Atlantic water, such as the eastern Fram Strait, the Barents Sea, and parts of the Eurasian Basin. Regions of the Arctic Ocean influenced by Pacific water exhibit a significant positive trend in TEP concentration, including the Amerasian Basin, the Canadian Arctic Archipelago and the Kara Sea.
In the second part of my thesis, I re-analyze the simulated environmental variables in order to ascertain their role as TEP drivers in three exemplary regions. The analysis demonstrates that TChla is an important predictor for TEP occurrence in general, but also physical factors such as photosynthetically active radiation and sea ice concentration exert a significant influence on the distribution of TEP in the Laptev Sea, while nutrient availability plays an important role in shaping the time series observed in the Fram Strait.
In the third part, I asses the long-term trend of TEP in the Arctic Ocean following a high-emission scenario proposed by the Intergovernmental Panel on Climate Change. The Arctic-wide TEP concentration is projected to increase significantly from 80 to 105 µg C/L in the upper ocean until 2100. This increase is driven mostly by the retreat of the sea ice cover, which triggers increases in phytoplankton carbon concentration and a subsequent increase in phytoplankton nutrient limitations. However, there are regional differences as, e.g., in the western Fram Strait, the trends seem to be shaped by the sea ice retreat and light availability, whereas in the eastern Fram Strait, nutrient availability and remineralization of TEP are important factors.
The final part of my dissertation revisits the role of biogenic aerosol precursors in the upper ocean. I briefly discuss one application of the knowledge gained about the organic carbon cycle in the upper Arctic Ocean. By serving as an ocean-atmosphere boundary condition, the simulation enables the determination of primary marine organic aerosol emissions in an aerosol-climate model. I conclude with a discussion on two perspectives for future research, namely the simulation of organic matter enrichment at the ocean surface and the distribution of TEP in the water column, especially with respect to sinking and degradation processes
Organic aerosol precursors from the Arctic Ocean - coupled ecosystem ocean modelling compared to in-situ and satellite observations
Full text linkConference Tal
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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