1,721,041 research outputs found
Physical and biological patchiness of an upper ocean transect from South Africa to the ice edge near the Greenwich Meridian
No full textAn undulating CTD (SeaSoar) was towed from the Subtropical Front at 42°S, 12°E to the ice edge at 57.5°S, 2°W. The instrument measured temperature, salinity, pressure, and light in the top 400 m of the water column. Fluorescence and particle counts also were recorded. Fluorescence was calibrated to chlorophylla, and particle counts were converted to biovolume to provide estimates of phyto- and zooplankton, respectively. The size of particles counted covered the range 0.25–8.0 mm.Three major fronts, Subtropical, Subantarctic, and Polar were intersected and identified by their physical characteristics. The Polar Front showed surface and subsurface signatures separated by nearly 300 km. Considerable small-scale structure was observed between the fronts, in particular a large (150-km diameter), warm-core eddy was found in the northern part of the Subantarctic Zone.Both fronts and eddy were associated with significant biological signals. Phyto- and zooplankton correlated well in the frontal regions and south of the Polar Front. The Polar Frontal Zone was associated with elevated concentrations of biomass, whereas concentrations were low at the Subantarctic Front and south of 55°S. In contrast, the warm-core eddy in the Subantarctic Zone contained the highest zooplankton biovolume of the section while chlorophyll concentration was only moderate. We hypothesise that such a distribution results from grazing.The overall distribution of phyto- and zooplankton changed across the Subantarctic Front. The vertical extent of biomass deepened from north to south across the front. Zooplankton tended to be concentrated in relatively narrow, deep-extending bands to the north but were more widely spread to the south. The small-scale hydrographic structure correlated significantly with the distribution of plankton, suggesting strong physical controls on both small zooplankton and phytoplankton.<br/
Zooplankton distribution and behaviour in the Southern Ocean from surveys with a towed Optical Plankton Counter
No full textSpatial distributions of zooplankton with lengths between about 500 ?m and 8 mm are described from surveys in the vicinity of the Antarctic Polar Front in austral summer 1995/6 using an Optical Plankton Counter mounted on a towed profiling SeaSoar. The distributions, split into several logarithmically spaced size classes, are compared and related to the physical environment south of the Polar Front in the Antarctic Zone and within the Polar Frontal Zone. They also are compared with phytoplankton distributions determined from surface chlorophyll data. Both phytoplankton and zooplankton carbon densities are low in the Antarctic Zone (2–3 g C m?2), but rise to larger values in the Polar Frontal Zone (5–7 g C m?2 for zooplankton and a maximum of 6 g C m?2 at fronts for phytoplankton). Calibration of OPC derived zooplankton biovolume to carbon was achieved by comparison with dry weights from multinet samples deployed in conjunction with CTD casts. The net data showed that over 98% of zooplankton counts were copepods. Diel behaviour also was examined. Only larger copepods (over 2 mm long) displayed significant diel migration, and then only 10–20% of the standing stock; the majority remained deeper than about 100 m and their distribution patterns suggest that they may be retained aside from the main frontal jets by ageostrophic circulations associated with the front. Copepods shorter than 2 mm rose from depth over the month-long survey to become concentrated in the surface layer (the top 70–100 m). The largest copepods that could be resolved, with lengths of about 4–8 mm (possibly Rhincalanus gigas), displayed unexpected behaviour in tending to migrate to the top 0–10 m by day, descending to 40–50 m each night
Plankton ecology and biogeochemistry in the Southern Ocean: a first review of Southern Ocean JGOFS
No full text
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
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
- …
