186,491 research outputs found
Estimating the distribution of demand for Antarctic krill (Euphauisa superba) from land-based predators at South Georgia
No full textSouth Georgia is renowned for the abundance of Antarctic krill (Euphausia superba) and a range of krill predators. Variability in krill availability at a range of scales, and the consequences of this for predator-prey interactions, mean that quantifying the spatially explicit demand for krill by those predators is essential to understanding the mechanisms underlying ecosystem changes in the region. In this thesis demand within a distinct study box to the northwest of the island has been assessed. The thesis has three sections; (1) the number of predators; (2) the distribution of predators; and (3) the demand for krill by those predators.
(1) Predator densities with confidence intervals were determined from appropriately designed shipboard transect survey; counts of Antarctic fur seals (Arctocephalus gazella), macaroni penguins (Eudyptes chrysolophus), gentoo penguins (Pygoscelis papua), and Antarctic prions (Pachyptila desolata) were adjusted for sea state, distance from observer and dive behaviour. Providing the first at-sea predator density estimates for the region.
(2) A comparison of the distribution of female Antarctic fur seals engaged in pup-rearing (using satellite telemetry) and the whole population that were not restricted to a single part of the population (from shipboard transect survey) was undertaken. Using two general additive models based on the relationship between seal distribution (one derived from transect and the other from telemetry) and the physical environment indicated that the spatial distribution of lactating females is representative of the general population.
(3) Using the derived predator density, the local krill demand estimate was 2581 tonnes krill per day, a consumption rate of 0.45% per day of the concurrently estimated krill biomass (using shipboard acoustics). Antarctic fur seals accounted for 75% of this demand. This level of demand was less than the increase in biomass resulting from krill growth. However, based on the length-specific demand, determined from concurrent predator diet samples demand exceeded growth for krill >48mm
Exploitation of the marine ecosystem in the sub-Antarctic: historical impacts and current consequences - Corrigendum
No full textSince the publication of Trathan & Reid (2009), it has come to my attention that in preparing the opening sections of the manuscript I inadvertently omitted an important citation to work by K-H. Kock (2000) that was of great assistance.In recognition of this, I consider that it is important and appropriate to correct this oversight by highlighting this earlier piece of work</p
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
The fishery for Antarctic krill – conflicts between industrial production, protection of biodiversity, and legal governance
No full textThe Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is responsible for conserving the Antarctic marine ecosystem, where conservation also includes the management of commercial fisheries. The largest fishery (by weight) in Antarctic waters is that for Antarctic krill, a species vital to biogeochemical cycles and carbon sequestration, and a critical dietary item for a broad guild of marine predators. Fishing interests grew from the 1960s onwards, but catches then declined following the breakup of the Soviet Union. Now catches are again increasing, CCAMLR has been developing a revised krill fishery management framework intended to reduce ecosystem risks to predators at critical times of year. At the CCAMLR meeting in 2024, ongoing development of the revised framework was considered, however no progress was made. Progress is urgent, since part of the existing management approach was not renewed. Consequently, by default, catches in the southwest Atlantic may now aggregate in space and time; the interim catch limit for krill (620,000 t) can now be taken from anywhere and at any time, including at times and in places critical to krill predators, possibly with unintended consequences. Allowing catches to aggregate in space and time is something CCAMLR has long sought to avoid. Existing voluntary measures implemented by the fishery will help distribute catches, but are no substitute for de jure management. In addition to risks to the ecosystem, the current situation also presents risks for fishing nations and for CCAMLR itself. Rapid progress with the revised management framework now depends upon rebuilding consensus.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
No full textWe 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
Dr. Edward P. Wimberly, ITC, July 2011
No full textThis video is a conversation with Dr. Edward P. Wimberly. Dr. Wimberly talks about his book, "No Shame in Wesley's Gospel: A Twenty-First Century Pastoral Gospel". Brad Ost, AUC Woodruff Library, is the interviewer
Author Rights and Scholarly Publishing
No full textOriginally posted at
http://blog.library.gsu.edu/2014/10/24/author-rights-and-scholarly-publishing/</p
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