1,721,138 research outputs found
MIS 13 and MIS 11 aggradational successions of the Paleo-Tiber delta: Geochronological constraints to sea-level fluctuations and to the Acheulean sites of Castel di Guido and Malagrotta (Rome, Italy)
No full textThis contribution presents an application of the conceptual model of 'aggradational succession' (i.e., the sedimentary record deposited in response to sea-level rise during the glacial terminations) to a series of geological sections of the Paleo-Tiber delta cropping out along the Via Aurelia near Rome, Italy. The geochronological constraints provided here through 40Ar/39Ar dating of volcanic layers intercalated within the sedimentary deposits of the MIS 13 and MIS 11 aggradational successions resulted in some remarkable outcomes: 1) we reconstruct an independent chronology of the Mediterranean sea-level oscillations 450 through 380 ka, in good agreement with the δ18O and the Red Sea relative sea level curve chronology; 2) the Glacial Termination V is here bracketed in the interval 423.1 ± 4.4–438.7 ± 1.2 ka; 3) we show that the aggradational successions of MIS 11 and MIS 13 display similar spatial/geometric features despite the significantly different amplitude of their Oxygen isotope records, challenging the regression models linking absolute values of benthic foraminifera δ18O and ice-volume; 4) we show the relevance of a climatic-stratigraphic approach in dating coastal-to-fluvial sedimentary contexts; 5) we provide indirect age constraints with the precision of a few ka for two important palaeoanthropological and archaeological sites in central Italy bearing Acheulean lithic industries and human remains
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
Magnetostratigraphy and 40Ar/39Ar dating of CAMP lava flows at the Triassic-Jurassic boundary, Morocco
No full textkoamabayili/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
The Central Atlantic Magmatic Province at the Triassic-Jurassic boundary: paleomagnetic and 40Ar/39Ar evidence from Morocco for brief, episodic volcanism
No full textThe Central Atlantic Magmatic Province (CAMP), one of the largest known flood basalt provinces formed in the
Phanerozoic, is associated with the pre-rift stage of the Atlantic Ocean at the Triassic–Jurassic boundary ca. 200 Ma.
Paleomagnetic sampling targeted packages of CAMP lava flows in Morocco’s High Atlas divided into four basic units (the
lower, intermediate, upper, and recurrent units) from sections identified on the basis of field observations and geochemistry.
Oriented cores were demagnetized using both alternating field (AF) and thermal techniques. Paleomagnetic results reveal
wholly normal polarity interrupted by at least one brief reversed chron located in the intermediate unit, and reveal distinct pulses
of volcanic activity identified by discrete changes in declination and inclination. These variations in magnetic direction are
interpreted as a record of secular variation, and they may provide an additional correlative tool for identification of spatially
separated CAMP lava flows within Morocco. 40Ar/39Ar analyses of Moroccan CAMP lavas yield plateau ages indistinguishable
within 2r error limits, sharing a weighted mean age of 199.9F0.5 Ma (2r), reinforcing the short-lived nature of these eruptions
despite the presence of sedimentary horizons between them. Correlation of our sections with the E23n, E23r, E24 sequence
reported in the Newark basin terrestrial section and St. Audrie’s Bay marine section is suggested. Brief volcanism in sudden
pulses is a potential mechanism for volcanic-induced climatic changes and biotic disruption at the Triassic–Jurassic boundary.
Combination of our directional group (DG) poles yields an African paleomagnetic pole at 200 Ma of k(8N)=73.08,
/(8E)=241.38 (Dp=5.08, Dm=18.58)
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