1,720,962 research outputs found
Impact of land-use change on bird communities of a Rwandan biodiversity hotspot
Get PDFAlthough land-use change is increasingly flagged as the top driver of biodiversity loss in the tropics, there are important information gaps on its effects on particular facets of biodiversity, particularly in the Afrotropics. To contribute to this research agenda, and with a focus on birds, this study explores how the varying degrees of anthropogenic habitat transformations have affected the patterns of species composition, species diversity, functional and phylogenetic diversity. The study employed a range of methods, however, the core results are based on avian point-count sampling and habitat assessment conducted within major land-use types in the Nyungwe landscape, a tropical montane rainforest and adjacent croplands in Rwanda. Further data on avian functional traits were obtained from museum specimens. The study shows the following in relation to relatively undisturbed forest habitats of the Nyungwe landscape. 1) Species composition was altered and species diversity levels declined in all alternative land-uses. 2) Restored and cultivated areas experienced loss of functional diversity, with steeper falls for the trophic-related traits in the former land-use. 3) Phylogenetic diversity was stable across land-uses, except for cultivated areas, which registered marked declines, particularly in monoculture farms of tea. 4) At the landscape scale, avian diversity was influenced by elevation, soil moisture and the lower vegetation height, however, within cultivated areas and regenerating forests, vegetation composition, and tree cover extent were of high importance. 5) There was no evident superiority of the assisted natural regeneration approach over the passive restoration approach with respect to supported avian diversity, reflecting the long time needed for a full recovery. This study provides evidence of the irreplaceability of primary forests in the tropics, and the crucial roles habitat heterogeneity plays in maintaining avian diversity. The thesis also considers how these findings may inform the conservation planning of multiple-use landscapes in Rwanda, and similar landscapes in the tropics, with attention also to the use of birds as flagships for conservation
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
Phytosociological Study of Nyungwe Montane Savannahs
Get PDFIt is uncommon to find savannahs encompassed into tropical montane rainforests. The case of Nyungwe savannahs is one of these particularities and until now no explanation on their origin, structure and dynamics was given. This unprecedented research documented special floristic diversity of montane savannahs of Nyungwe, described the structure of their plant communities to provide data for their sustainable conservation. In this paper origin of these savannahs was discussed. The study was conducted in three sites harbouring five savannahs:Karamba, Nyabitimbo and Muzimu. Eight plant communities (4 in savannah-forest contact zone and other 4 in savannah) were identified with 198 species. Vascular species were distributed in 71 families. Phytogeographic distribution analysis of species showed the predominance of afromontane species (Mo) in sampled savannahs (31%), followed by East African montane species (Mo, EA) with 22% of all species. Montane endemism proved the predominance of ‘relatively restricted endemic species’ identified in 2or3 montane systems (among Kivu-Ruwenzori, ImatongsUsambara, UluguruMlanje, and Ethiopia with 41.1%) followed by ‘afromontane endemic wades’ identified in 4to7 systems representing 39.9%). ‘Local endemic montane species’ represented 31% of all species. Thus, these savannahs are favourable to species coming from almost seven African montane systems. Keywords: Nyungwe, Plant communities, montane savannahs
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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