1,720,957 research outputs found
Observations of oceanic potential vorticity and its relationship with other tracers
No full textDriven by interest in measuring the oceanic velocity field from space, sea surface temperature (SST) has been suggested as a proxy for potential vorticity (PV), which may then be inverted to give velocity. However, little is known about the relationships between PV and other water mass tracers, as these have not previously been thoroughly examined. In this thesis, the inter-relationships between PV, SST, potential temperature and salinity in three quite different frontal regions of the ocean are investigated. The regions studied were in the North-east Atlantic, the Sargasso Sea and the Bellingshausen Sea (Southern Ocean).The only earlier work known in this field was by Fischer et al. (1989), which found a near-linear relationship between PV and isopycnic potential temperature on a shallow isopycnal in the North Atlantic. This relationship was also evident in climatological values of PV and temperature in the North Atlantic. The results from the three regions considered in this thesis vary considerably, and are believed to be due to different frontal dynamics and water mass formation mechanisms. All the North-east Atlantic results are in close agreement, despite differences in measurement scales and the year of survey.The reasons for different relationships occurring are examined. Theories for setting PV and tracer values are investigated, and in particular the models of Woods (1985) and Spall (1995) are found to explain the relationships found in the North-east Atlantic and Sargasso Sea, respectively. However, a combination of these models, applied to different scales of motion, is needed to explain the Bellingshausen Sea results. Preliminary work iscarried out using a one-dimensional computer model to follow the development of the relationship in the north-east Atlantic
CTD and XBT data collected on ERS-1 validation cruise RRS Charles Darwin Cruise 62A, Iceland-Faeroes region
Full text linkCTD data collected on RRS "Discovery" Cruise 198 (Sterna) in the Bellingshausen Sea and along 88W
No full textSeaSoar data collected on RRS "Discovery" Cruise 198 (Sterna) across Drake Passage and in the Bellingshausen Sea
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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
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
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