1,721,047 research outputs found
The Postglacial Isotopic Record of Intermediate Water Connects Mediterranean Sapropels and Organic‐Rich Layers
Full text linkCarbon‐rich layers exist at both sides of the Mediterranean Sea sedimentary record and are
called sapropels and organic rich layers (ORLs), respectively, in the eastern and western basins. They
have different levels of organic carbon accumulation and seafloor oxygen deprivation. The most recent
sapropel and ORL depositions have a different timing, approximately 10.8–6.1 and 14.5–9.0 ka, respectively.
Here we investigate oxygen isotopic records of three foraminifera species that occupy different habitats
within the Sicily Channel water column since ~12.0 ka, thus in the sill between the eastern and western
Mediterranean basins. These data are ice volume corrected, to get information on water masses density
variability, and are accompanied by benthic foraminifera δ13C measurements to establish Sicily Channel
seafloor ventilation. Our results, and the comparison with other chronologically well‐constrained
Mediterranean records, highlight the connection of the two subbasins due to monsoon activity. The end of
the maximum Nile River flooding at ~9.2 ka, and eastern Mediterranean seafloor reventilation above
1,800–1,500 mdepth at ~ 8.2 and 7.2 ka, left a clear signature in the intermediate water isotopic record of the
Sicily Channel. Concurrently, the western Mediterranean deep water circulation experienced a
significant recovery after a long period of slowdown. We argue that African monsoon weakening was
transmitted into the western Mediterranean, through the intermediate layer of circulation, where deep
water formation took place and brought oxygen to the seafloor
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
A MILANKOVITCH CLIMATE CONTROL ON THE MIDDLE MIOCENE MEDITERRANEAN INTERMEDIATE WATER.
No full textThe marly sediments of the Blue Clay Formation in the upper part of the Middle Miocene Ras il-Pellegrin composite section (Malta island, central Mediterranean) have been investigated by integrated analysis of benthic microfauna and planktonic and benthic oxygen isotopes. The astronomical calibration of the whole section, obtained by using the astronomical solution of Laskar et al. (1993), indicates for deposition of the analysed sediments a time interval ranging between 13.75 and 12.32 Ma (Sprovieri et al., 2002). This time interval is useful to investigate the oceanographic evolution of the (paleo)Mediterranean after the interruption of communications between the Mediterranean and Indo-Pacific areas. This important paleogeographic event, estimated at about 16 Ma by Johnson (1985) and at about 14.5 Ma by Woodruff and Savin (1991), represented the first step of a progressive oceanographic evolution of the Tethys region water masses towards present Mediterranean conditions. A comparison of long-term planktonic and benthic d18O trends suggests that the intermediate outflowing Mediterranean water (proto-MIW), originated in the surface eastern zone of upper Langhian lower Serravallian (paleo)Mediterranean, had hydrographic and hydrodynamic features similar to those of the present Levantine Intermediate Water (LIW). Focusing our attention on benthic species which can be considered the best recorders of variation of proto-MIW production, we elaborated benthic data by Q-mode varimax principal factor analysis. Spectral analysis was carried out only on two factors which have a clear paleoecological significance: Factor 1 (loaded by Cibicidoides ungerianus and Siphonina reticulata) indicative of oxic bottom waters and Factor 2 (loaded by Bulimina elongata group) indicative of oxygen stressed conditions. Results of these analyses show that Factor 1 and Factor 2 curves are respectively in and out of phase with maxima of the eccentricity (100 and 400 kyr). Factor 1 is interpreted as a tracer of high production of proto-MIW, during periods of high eccentricity and, probably, precession minima, characterized by coldest winter seasons. These results point out a direct link between selected benthic species, long term astronomical forcing, and deep water response and provide an useful tool for astronomical calibration of geological time and paleoceanographic reconstructions
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
- …
