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An oxygen isotope record fromthe Foscagno rock-glacier ice core,Upper Valtellina, Italian Central Alps
No full textNew high-resolution isotopic records (delta O-18, delta D and deuterium excess), from an ice core drilled in the Foscagno rock glacier ( Italian Central Alps), are presented. The delta O-18 data suggest a clear division between an upper part (2.5 and 4 m), showing relatively homogeneous values, and a middle part (4 - 7.65 m), showing seasonal variations of this parameter. The isotopic analyses confirm previous results (crystallographic and chemical analyses) suggesting a division of this relict glacier ice body into an upper part, between 2.5 and 4 m, where melting and refreezing processes occur, and a middle part, between 4 and 7.65 m, where the isotopic signal is preserved. Larger deuterium excess variations (d = delta D - delta*delta O-18) are found in the massive ice (below 4 m depth) rather than in the overlying ice. These are in antiphase with the delta O-18 but without any clear correspondence with the presence of the debris layers. Postdepositional processes could have affected, at least partially, the isotopic content of the original precipitation. The radiocarbon dating of a leaf (Salix spp.) found in the massive ice from another nearby borehole in the same rock glacier gave a calendar age ranging between AD 765 and 1260. The expected delta O-18 values of the present-day precipitation in the Foscagno valley are of the same order as those found in the massive ice (-12.4%). This similarity would suggest climate conditions not very different from present day, in good agreement with other available palaeoclimate reconstructions for this period. However, only more abundant precipitation would make the existence of a glacier possible in a climate not very different from that of the present
An oxygen isotope record from the Foscagno rock glacier ice core (Upper Valtellina, Italian Central Alps)
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Volcanic Records at GPS1, GPS2, 31DPT and M2 Stations along the 1998-99 ITASE Traverse (East Antarctica).
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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
Oxygen isotope measurements of mammoth and reindeer skeletal remains: an archive of late Pleistocene environmental conditions in Eurasian Arctic
No full textAppropriate 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
An oxygen isotope record from the Foscagno rock glacier ice core (Upper Valtellina, Italian Central Alps)
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