1,721,049 research outputs found
Implications of increasing Atlantic influence for Arctic microbial community structure
Full text linkIncreasing influence of Atlantic water in the Arctic Ocean has the potential to significantly impact regional water temperature and salinity. Here we use a rDNA barcoding approach to reveal how microbial communities are partitioned into distinct assemblages across a gradient of Atlantic-Polar Water influence in the Norwegian Sea. Data suggest that temperate adapted bacteria may replace cold water taxa under a future scenario of increasing Atlantic influence, but the eukaryote response is more complex. Some abundant eukaryotic cold water taxa could persist, while less abundant eukaryotic taxa may be replaced by warmer adapted temperate species. Furthermore, within lineages, different taxa display evidence of increased relative abundance in reaction to favourable conditions and we observed that rare microbial taxa are sample site rather than region specific. Our findings have significant implications for the vulnerability of polar associated community assemblages, which may change, impacting the ecosystem services they provide, under predicted increases of Atlantic mixing and warming within the Arctic region
On the double-diffusive and cabbeling environments of the Arctic Front, West Spitsbergen
No full textThis paper describes the thermohaline characteristics of the Arctic Front to the west of Spitsbergen, in terms of the double-diffusive environment and the potential for densification through cabbeling. The front separates the warm, saline Atlantic water in the West Spitsbergen Current from the cooler, fresher water on the West Spitsbergen Shelf. We have investigated processes at the front that can contribute to, or enhance, mixing and water mass modification in relation to heat transport to the Arctic. Hydrographic data were collected along a cross-shelf section in September 2005. The double-diffusive properties along the section were determined by calculating Turner angles, and cabbeling was investigated with a simple linear mixing scheme. Double diffusion, in the form of diffusive layering, was found to be active within the Arctic Front, with considerable interleaving between water masses. Furthermore, mixing of water masses across the front was found to generate a potential increase in density of more than 0.03 kg m -3 through cabbeling, which would then promote sinking and convergence. Our analyses indicate that the two processes of double diffusion and cabbeling are active at the Arctic Front. We discuss their potential contribution to maintaining the density-compensated nature of the front, and conclude that they will promote isopycnal mixing and subsequent modification of the core water of the West Spitsbergen Current
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
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
Eat or sleep : availability of winter prey explains mid-winter and spring activity in an arctic Calanus population
Full text linkCopepods of the genus Calanus have adapted to high levels of seasonality in prey availability by entering a period of hibernation during winter known as diapause, but repeated observations of active Calanus spp. have been made in January in high latitude fjords which suggests plasticity in over-wintering strategies. During the last decade, the period of Polar Night has been studied intensively in the Arctic. A continuous presence of an active microbial food web suggests the prevalence of low-level alternative copepod prey (such as microzooplankton) throughout this period of darkness. Here we provide further evidence of mid-winter zooplankton activity using a decadal record of moored acoustics from Kongsfjorden, Svalbard. We apply an individual based life-history model to investigate the fitness consequences of a range of over-wintering strategies (in terms of diapause timing and duration) under a variety of prey availability scenarios. In scenarios of no winter prey availability ((Formula presented.)), the optimal time to exit diapause is in March. However, as P win increases (up to 40μgCL −1), there is little fitness difference in copepods exiting diapause in January compared to March. From this, we suggest that Calanus are able (in energetic terms) to either i) exit diapause early to deal with uncertainty in spring bloom timing, or ii) remain active throughout winter if diapause is not possible (i.e., environment not deep enough, or not enough lipid reserves built up over the previous summer). The range of viable overwintering strategies increases with increasing P win, suggesting that there is more flexibility for Calanus spp. in a scenario of non-zero P win
- …
