1,720,967 research outputs found
Authigenic neodymium isotope data from deep sea sediment from the Southern Atlantic Ocean back to the the Mid Pleistocene Transition
No full textWe present authigenic neodymium isotope data (εNd) from two sediment cores from the Atlantic sector of the Southern Ocean (SO). The samples were prepared with a weak leach solution and measured with the ThermoFisher Neptuneplus MC-ICPMS at the Institute of Environmental Physics in Heidelberg. Both investigated sites are located south of the modern polar frontal zone within the modern mixing zone of Circumpolar Deep Water and Antarctic Bottom Water. The following data sets extend the data from Hallmaier et al. (2025) (https://doi.org/10.1594/PANGAEA.956277) far back to the Mid Pleistocene Transition. The Nd isotopic data from site ODP 1093 forms a continuous record from 150 ka to 1 Ma with a millennial resolution. It reveals a strong variability synchronous to the ice volume and thus the global climate with radiogenic glacial and unradiogenic interglacial values for the past 30 MIS. The measurements of the sediment from site ODP 1094 cover MIS 11-12 and the time around the 900 ka event. The data shows a transition from an unradiogenic signal of low variability prior to the 900 ka event to a highly variable signal for the time after
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
Authigenic Uranium Preservation and Bottom Water Oxygenation in the Scotia Sea
No full textSedimentary uranium (U) and thorium (Th) isotopes are invaluable proxies to assess paleo export productivity and bottom water redox conditions, site-specific sediment focusing and vertical rain rates.
We report authigenic uranium at IODP Site U1537 in the Scotia Sea and further provide bulk sediment δ234U, Th-normalized vertical rain rates, bulk element concentrations, porewater U concentration, biogenic barium and opal concentrations. Multiple proxies point to increased export productivity during interglacials in the Scotia Sea. During interglacials, the accumulation of authigenic U is controlled by the decomposition of substantial quantities of organic matter, caused by the high export productivity. Conversely, during glacial times, low export productivity is coinciding with low authigenic U, suggesting well-oxygenated bottom waters. Further, we gain new information on the development of Weddell Sea Deep Water export across the last termination into the Scotia Sea. The age model used for the last 150 ka is from Lu et al. (2022), and for earlier periods from Weber et al. (2022)
Authigenic neodymium isotope data of sediment cores from the deep South Atlantic
No full textHere, we present neodymium isotope data (εNd) from three sediment cores from the Atlantic sector of the Southern Ocean (SO) to assess the distribution of water masses during the past 150 ka. The cores are located south of the modern polar frontal zone, building a vertical transect within the modern mixing zone of Circumpolar Deep Water and Antarctic Bottom Water. The data reveals a tremendous εNd variability, which reflects mainly water mass changes during climate transitions. It resolves systematic glacial-interglacial variations in the deep-water composition with strong evidence of a persistent admixture of Pacific sourced water into the SO during the past 150 ka which is the strongest during times of peak glacial ice extent. Mass spectrometric Nd isotope measurements were performed at the Institute of Environmental Physics multicollector ICPMS facility in Heidelberg, which hosts a ThermoFisher Neptuneplus MC-ICPMS coupled with an APEX HF desolvating system and an ESI-SC autosampler
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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