1,721,388 research outputs found
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
The role of climate and biotic factors in shaping current distributions and potential future shifts of European Neocrepidodera (Coleoptera, Chrysomelidae)
No full textThe Western Paleartic species of Neocrepidodera Heikertinger (Coleoptera: Chrysomelidae: Galerucinae: Alticini) mostly occur in medium and high elevation ecosystems particularly sensitive to climate change. Here, using ensemble projections from state-of-the-art habitat suitability modelling techniques, we investigated how climate change and associated changes in host availability may affect the persistence of three pairs of closely related Neocrepidodera taxa. Modelled niches and suitability patterns reflected the current distributions of the targeted taxa. Neocrepidodera ligurica occupies a small portion of the broader environmental niche of N. melanostoma, and its narrow geographical range makes this species particularly vulnerable to potential loss of suitable habitats in Western Alps. Neocrepidodera cyanescens cyanescens and N. cyanescens concolor were found to occupy separate niches, but the non-significance of the niche similarity test suggested their divergence being probably due to allopatric processes. Neocrepidodera corpulenta and N. rhaetica showed partially overlapping niches, coherently with their co-occurrence in Western Alps. Most of the targeted taxa were predicted to potentially lose large portions of currently suitable areas in the forthcoming decades. Notwithstanding the candidate host plants did not emerge as most important predictors, except Aconitum lycoctonum for N. cyanescens concolor, a clear reduction of potential insect-plant co-occurrence areas resulted for most future scenarios. Climate was confirmed to noticeably affect the distribution of the targeted taxa, among which N. ligurica, N. cyanescens concolor, N. corpulenta and N. rhaetica may need specific prioritisation measures in the future decades, claiming for further attention on mountainous entomofauna in a warming world
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
Darwin’s naturalization hypothesis: scale matters in coastal plant communities
No full textDarwin proposed two seemingly contradictory hypotheses for a better understanding of biological invasions. Strong
relatedness of invaders to native communities as an indication of niche overlap could promote naturalization because of
appropriate niche adaptation, but could also hamper naturalization because of negative interactions with native species
(‘Darwin’s naturalization hypothesis’). Although these hypotheses provide clear and opposing predictions for expected
patterns of species relatedness in invaded communities, so far no study has been able to clearly disentangle the underlying
mechanisms. We hypothesize that conflicting past results are mainly due to the neglected role of spatial resolution of the
community sampling. In this study, we corroborate both of Darwin’s expectations by using phylogenetic relatedness as a
measure of niche overlap and by testing the effects of sampling resolution in highly invaded coastal plant communities.
At spatial resolutions fine enough to detect signatures of biotic interactions, we find that most invaders are less related to
their nearest relative in invaded plant communities than expected by chance (phylogenetic overdispersion). Yet at coarser
spatial resolutions, native assemblages become more invasible for closely-related species as a consequence of habitat filtering
(phylogenetic clustering). Recognition of the importance of the spatial resolution at which communities are studied
allows apparently contrasting theoretical and empirical results to be reconciled. Our study opens new perspectives on how
to better detect, differentiate and understand the impact of negative biotic interactions and habitat filtering on the ability
of invaders to establish in native communities
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
Disentangling the relative effects of environmental versus human factors on the abundance of native and alien plant species in Mediterranean sandy shores
No full textAim: Mediterranean coastal sand dunes are characterized by both very stressful environmental conditions and intense
human pressure. This work aims to separate the relative contributions of environmental and human factors in
determining the presence/abundance of native and alien plant species in such an extreme environment at a regional
scale.
Location. 250 km of the Italian Tyrrhenian coast (Region Lazio).
Methods: We analysed alien and native plant richness and fitted generalized additive models in a multimodel-inference
framework with comprehensive randomizations to evaluate the relative contribution of environmental and human
correlates in explaining the observed patterns.
Results: Native and alien richness are positively correlated, but different variables influence their spatial patterns. For
natives, human population density is the most important factor and is negatively related to richness. Numbers of
natives are unexpectedly lower in areas with a high proportion of natural land cover (probably attributable to local
farming practices) and, to a lesser degree, affected by the movement of the coastline. On the other hand, alien
species richness is strongly related to climatic factors, and more aliens are found in sectors with high rainfall.
Secondarily, alien introductions appear to be related to recent urban sprawl and associated gardening.
Main conclusions: Well-adapted native species in a fragile equilibrium with their natural environment are extremely sensitive to human-driven modifications. On the contrary, for more generalist alien species, the availability of limited resources plays a predominant role
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