1,720,983 research outputs found
On the frozen edge: Environmental and physiological constraints in the life history of a northerly-wintering shorebird
Get PDFDe populatie Calidris p. ptilocnemis (hierna: ptilocnemis), een ondersoort van de Beringstrandlopers, telt ongeveer 20.000 individuen. Deze ondersoort overwintert in het noorden van Cook Inlet, Alaska (61°N, 151°W). Dit is voor zover bekend het meest noordelijk gelegen overwinteringsgebied voor steltlopers in de gehele Stille Oceaan en het is bovendien het koudste gebied dat regelmatig overwinterende wadvogels herbergt. De extreme condities in het noorden van Cook Inlet zorgen voor hoge verblijfskosten en de jaarlijkse aangroei van zee- en landijs veroorzaken onvoorspelbare en moeilijke foerageer-omstandigheden voor de strandlopers. Op een experimentele manier, door de strandlopers van Alaska naar Texel te brengen, hebben we de energiehuishouding en het foerageergedrag van ptilocnemis vergeleken met een andere ondersoort van de Beringstrandlopers C.p. tschuktschorum (hierna: tschuktschorum). Deze ondersoort heeft een meer zuidelijk gelegen overwinteringsgebied rond de Stille Oceaan, langs de noordwest kust van Noord Amerika, waar de omstandigheden aanzienlijk milder zijn. De twee ondersoorten vertoonde vergelijkbare toenames in energieverbruik met temperatuurverlagingen, maar in vergelijking met tschuktschorum vertoonde ptilocnemis belangrijke verschillen in foerageer-ecofysiologie die voor een hogere energie-opname en doorstroom van de in de maag gekraakte schelpresten zorgde. Dit is waarschijnlijk het resultaat van fysiologische verschillen tussen de twee ondersoorten in verteringstelsel en niet van verschillen in foeragee gedrag of de begaafdheid in het vinden van prooien. In het wild vergroot ptilocnemis de maag en lever om de stofwisseling sneller en efficiënter te laten verlopen. Tegelijkertijd worden vetreserves opgeslagen die gebruikt worden om perioden van kou en voedselschaarste te kunnen overbruggen. Daarbij maakt de aanwezigheid van buitengewoon hoogwaardig voedsel in de vorm van Nonnetjes Macoma balthica het de steltlopers mogelijk hun winter door brengen in het hoge noorden van Alaska. Samengevat zorgen de aanwezigheid van deze hoogwaardige voedselbron in combinatie met de bovengenoemde fysiologische- en gedragsaanpassingen er voor dat ptilocnemis ondanks de ogenschijnlijke erbarmelijke omstandigheden in staat is te overwinteren in het koude Alaska
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
Reproductive success of American and Pacific golden-plovers (Pluvialis dominica and P. fulva) in a changing climate
Get PDFThesis (M.S.) University of Alaska Fairbanks, 2019Climate change is increasing air temperatures and altering hydrologic systems in arctic environments, which will create positive feedbacks on shrub growth and advance the phenology of arthropods, important prey for many Arctic-breeding birds. Little is understood about how such climate-induced changes in habitat and prey availability may affect reproductive success of migratory birds during the short arctic breeding season. Worldwide, declines in shorebird populations, including arctic-breeding species, have recently become apparent. Projected changes in climate are expected to benefit Arctic-breeding shorebirds in the short-term by increasing reproductive success and survival, primarily through prolongation of summer. Over time, however, reductions in the quantity and quality of open tundra habitat and changes in prey availability may adversely affect shorebird reproduction and exacerbate current population declines. I evaluated the reproductive success of two shorebird species, American (Pluvialis dominica) and Pacific (P. fulva) Golden-Plovers, in relation to vegetation extent and phenology. I collected data over two field seasons (2012-2013) on the Seward Peninsula, Alaska. Both species selected nest sites with less cover of tall shrubs and other tall vegetation than available at random sites within their territories. American Golden-Plovers selected territories and nest sites that were higher in elevation and had more rocky substrates and less graminoid vegetation than those selected by Pacific Golden-Plovers. Nest survival was equivalent in the two species and similar to that found in other arctic-breeding shorebirds. Over the 27-d incubation period the probability of a nest having at least one egg survive to hatch averaged 0.39 (95% CI: 0.28, 0.49). Nest survival was not explicitly associated with habitat features at nest sites; however, nest survival was lower during the year with earlier spring phenology and declined with the age of the nest, both of which may have been at least partially related to growth of vegetation. Future research should examine reproductive success in a comprehensive manner, in which multiple aspects of a species' reproductive ecology is evaluated, allowing a more complete understanding of the effects of climate change on recruitment into populations through the combined effects of habitat structure, food resources, and climate.Changing Arctic Ecosystems Initiative of the U.S. Geological Survey, Alaska Science Center, Arctic Audubon, the University of Alaska Fairbanks Global Change Grant, the University of Alaska Fairbanks Institute of Arctic Biology, and the Betty A. Anderson Memorial for Avian Studies Scholarshi
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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