1,721,108 research outputs found
Simulating atmospheric CO2 concentration for the Plio-Pleistocene using a new set of temperature and sea level reconstruction
No full textIn contrast to previous approaches, new reconstructions of changes in global mean surface temperature (Clark et al., 2024, doi: 10.1126/science.adi1908) and global mean sea level (Clark et al., 2025, doi: 10.1126/science.adv8389) include large variability in global mean sea level throughout the Pleistocene. Here we use them to force the global carbon cycle model BICYCLE-SE in different scenarios that capture the spread in existing CO2 reconstructions.
This data set contains:
- important otherwise not yet available data (4.5 Ma long time series of regional SST split by latitude (65°S-30°S | 30°S-30°N | 30°N-65°N) which have been used to force the model;
- resulting major changes in the simulated carbon cycle (mean ocean salinity; Atlantic meridional overturning strength; Southern Ocean vertical mixing; global sea ice area);
- simulated atmospheric CO2 in 3 scenarios that differ in volcanic CO2 outgassing and weathering strength
Physical and biogeochemical responses to freshwater-induced thermohaline variability in a zonally averaged ocean model
No full textFreshwater perturbation experiments are conducted with a latitude-depth, circulation-biogeochemistry ocean model coupled to an energy balance model of the atmosphere. The aim is to identify potential effects of different changes of the Atlantic thermohaline circulation (THC). Strong THC reductions (> 50%) lead to cooling at high northern latitudes and warming in the southern hemisphere. For moderate reductions, however, cooling in the north is not accompanied by temperature changes in the south. These results are discussed in relation with a recent synchronization of isotopic records from Greenland and Antarctic ice cores based on methane, which documents north-south thermal antiphasing during the largest Greenland δ18O oscillations and no clear Antarctic counterparts during the other, shorter oscillations of the last glacial period. Simulations show that strong THC reductions resultd in PO4 enrichment and δ13C depletion below 1 km in the North Atlantic reaching, on average, about 0.5 mmol m-3 and-0.3‰ for a complete THC collapse. These chemical and isotopic changes are due to an imbalance between organic matter oxidation and import of nutrient-poor waters from the northern North Atlantic. The THC reductions also lead to a drop in δ13C air-sea disequilibrium in the Atlantic where the surface waters stay longer in contact with the atmosphere. Thus, in the upper kilometer, cold waters in the northern North Atlantic become isotopically heavier (by more than 1%),whereas warm waters further south becomes lightly lighter (~ -0.2‰). The simulated chemical and isotopic shifts are much smaller below 1 km in the South Atlantic and Southern Ocean. These results indicate that the same circulation change could produce completely different PO4 and δ13C anomalies at different locations and depths in the Atlantic and Southern Ocean. This might have strong implications for the interpretation of marine Cd/Ca and δ13C sediment records obtained from different oceanic regions
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
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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