1,720,973 research outputs found
Repeatability of daily energy expenditure in kittiwakes Rissa tridactyla
Get PDFEstimates of repeatability (R) are an important statistic tool in assessing the consistency of individual differences and thus different phenotypes. A high repeatability of estimates of the daily energy expenditure (DEE), allow for better inferences of the long term energetic effort of individuals, as well as for sound correlations of other traits related to individual performance, such as reproductive success. Previously, measurements of DEE have been restricted to 24h, but the ecological relevance of such a time frame has been questioned. Estimates of DEE, using the doubly labelled water (DLW) method, were repeated on individuals of kittiwakes breeding on Svalbard, during four study years. The aim of the study was to investigate the time scale in which kittiwakes balance their energy expenditure. Repeatability of DEE was estimated using two different measurement intervals, measuring over a period of either 24h or 72h, within years as well as between years. In addition, it was investigated whether the less invasive single-sample (SS) DLW protocol could improve repeatability over the more common two-sample (TS) protocol, by allowing for kittiwakes to exhibit a near-natural behaviour. We found that individual DEE was repeatable both within (72h: R = 0.772) and between years (72h: R = 0.430) using the TS protocol and the long measurement interval. The short interval estimates were not significantly different from zero, although applying the SS protocol appeared to have an increasing effect on R. These findings demonstrate, that prolonging the length of the DEE measurement interval, caused a high increase in R, suggesting that kittiwakes budget their energy expenditure over a longer time period than 24 hours. The moderate to high R found between years suggest that kittiwakes are consistently different in their energy expenditure over longer periods of time. However, when adjusting for body mass (BM) only within-season repeatability was significant (72h: R = 0.652), which was mainly due to a high inter-individual variation in BM
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
Behavioral and energetic response of Arctic-breeding seabirds to environmental variability.
No full textKnowledge about the extent to which organisms inhabitating the Arctic are able to adjust to environmental variability is essential in order to predict the impact of future climate change. In this context, the flexibility og two Acrtic-breeding seabirds, the little Auk (Alle alle) and the kittiwake (Rissa tridactyla), in foraging behavior and energy expenditure in response to environmental variability. Analysis of the foraging behavior of little auks revealed the during chick-rearing this species adopts a bimodal foraging strategy in which they alternate single foraging trips of long duration with several trips of short length. This stereotyped pattern was found to be highly flexivle and adjusted to psatial and temporal variation in foraging conditions. However, behavioral modifications led to reduced chick feeding rates and lower reproductive success, indicating the adjustments did not allow birds to fully compensate for costs incurred by unfavorable conditions. Adjustment and limitation of energy expenditure differed remarkably between the two study species. Metabolic rate in little auks was flexible and adjusted in response to variation in food availability. Birds increased energy expenditure when food was abundant. Elevated metabolism was associated with increased chick provisioning, resulting in enhanced chick surival, and increased resource allocation to self-maintenance, associated with higher body mass and a higher return rate of individuals the subsquent season. In contrast, kittiwakes did not adjust their metabolic rate in response to environmental variability. In this species, metabolic rate was similar across five study years despite large variation in foraging conditions. Instead, kittiwakes seemed to operate close to an energetic ceiling which seemed independent of extrinsic factors. This study suggested a limited ability of Arctic seabirds to compensate for large variation to environmental conditions
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
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